Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius,...

144
Acids, Bases, and Salts hould be able to derstand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. entify strong acids and bases and calculate their pH’s. lculate the pH of a weak acid or base. lculate the concentration of a strong or weak acid or base from its pH. lculate the pH and ion concentration in a polyprotic acid. edict the pH of a salt from its formula and then calculate the pH of the salt. familiar with titration curves and selection of an acid-base indica

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Transcript of Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius,...

Page 1: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acids Bases and SaltsYou should be able to

Understand the acid-base theories of Arrhenius Broslashnsted-Lowryand Lewis

Identify strong acids and bases and calculate their pHrsquos

Calculate the pH of a weak acid or base

Calculate the concentration of a strong or weak acid or base from its pH

Calculate the pH and ion concentration in a polyprotic acid

Predict the pH of a salt from its formula and then calculate the pH of the salt

Be familiar with titration curves and selection of an acid-base indicator

pH scale

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

ACID BASE

NEUTRAL

Each step on pH scale represents a factor of 10

pH 5 vs pH 6 (10X more acidic)pH 3 vs pH 5 (100X different)pH 8 vs pH 13 (100000X different)

measures aciditybasicity

10x10x10x100x

Soslashren Sorensen(1868 - 1939)

Acid

Base

pH = -log [H1+]

pH = 7Acidic Basic

Neutral

[H+] [OH-][H+] = [OH-]

Acid vs Base

Acid

pH gt 7

bitter taste

does notreact with

metals

pH lt 7

sour taste

react withmetals

Alike Different

Related toH+ (proton)

concentration

pH + pOH = 14

Affects pHand

litmus paper

Base

Different

Topic Topic

Properties

electrolytes

turn litmus red

sour taste

react with metals to form H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar milk soda apples citrus fruits

ammonia lye antacid baking soda

electrolytes

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acidH2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz Purcell Chemistry amp Chemical Reactivity 1991 page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 2: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH scale

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

ACID BASE

NEUTRAL

Each step on pH scale represents a factor of 10

pH 5 vs pH 6 (10X more acidic)pH 3 vs pH 5 (100X different)pH 8 vs pH 13 (100000X different)

measures aciditybasicity

10x10x10x100x

Soslashren Sorensen(1868 - 1939)

Acid

Base

pH = -log [H1+]

pH = 7Acidic Basic

Neutral

[H+] [OH-][H+] = [OH-]

Acid vs Base

Acid

pH gt 7

bitter taste

does notreact with

metals

pH lt 7

sour taste

react withmetals

Alike Different

Related toH+ (proton)

concentration

pH + pOH = 14

Affects pHand

litmus paper

Base

Different

Topic Topic

Properties

electrolytes

turn litmus red

sour taste

react with metals to form H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar milk soda apples citrus fruits

ammonia lye antacid baking soda

electrolytes

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acidH2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz Purcell Chemistry amp Chemical Reactivity 1991 page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 3: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid

Base

pH = -log [H1+]

pH = 7Acidic Basic

Neutral

[H+] [OH-][H+] = [OH-]

Acid vs Base

Acid

pH gt 7

bitter taste

does notreact with

metals

pH lt 7

sour taste

react withmetals

Alike Different

Related toH+ (proton)

concentration

pH + pOH = 14

Affects pHand

litmus paper

Base

Different

Topic Topic

Properties

electrolytes

turn litmus red

sour taste

react with metals to form H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar milk soda apples citrus fruits

ammonia lye antacid baking soda

electrolytes

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acidH2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz Purcell Chemistry amp Chemical Reactivity 1991 page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 4: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid vs Base

Acid

pH gt 7

bitter taste

does notreact with

metals

pH lt 7

sour taste

react withmetals

Alike Different

Related toH+ (proton)

concentration

pH + pOH = 14

Affects pHand

litmus paper

Base

Different

Topic Topic

Properties

electrolytes

turn litmus red

sour taste

react with metals to form H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar milk soda apples citrus fruits

ammonia lye antacid baking soda

electrolytes

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acidH2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz Purcell Chemistry amp Chemical Reactivity 1991 page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 5: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Properties

electrolytes

turn litmus red

sour taste

react with metals to form H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar milk soda apples citrus fruits

ammonia lye antacid baking soda

electrolytes

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acidH2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz Purcell Chemistry amp Chemical Reactivity 1991 page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 6: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acidH2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz Purcell Chemistry amp Chemical Reactivity 1991 page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 7: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid + Base Salt + Water

bull Orange juice + milk bad tastebull Evergreen shrub + concrete dead bushbull Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOH

salt water

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 8: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 584

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 9: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Formation of Sulfuric Acid

Kelter Carr Scott Chemistry A World of Choices 1999 page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 10: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 11: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

CO2 (g)CO2 (g) H2O (l)H2O (l) H2CO3 (aq)H2CO3 (aq)

Carbon dioxideCarbon dioxide

Carbonic acid

Carbonic acid

WaterWater

Weak acid Weak acid

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 12: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizersand explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 13: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Common AcidsFormula Name of Acid Name of

Negative Ion of Salt

HF hydrofluoric fluorideHBr hydrobromic bromideHI hydroiodic iodideHCl hydrochloric chlorideHClO hypochlorous hypochloriteHClO2 chlorous chloriteHClO3 chloric chlorateHClO4 perchloric perchlorateH2S hydrosulfuric sulfideH2SO3 sulfurous sulfiteH2SO4 sulfuric sulfateHNO2 nitrous nitriteHNO3 nitric nitrateH2CO3 carbonic carbonateH3PO3 phosphorous phosphiteH3PO4 phosphoric phosphate

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 14: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Formation of Hydronium Ions

1+

hydronium ion

H3O+

+

hydrogen ion

H+

water

H2O

1+

(a proton)

1+

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 15: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Sulfuric Acid H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world

Uses petroleum refining metallurgy manufacture of fertilizer many industrial processes metals paper paint dyes detergents

Sulfuric acid is used in automobile batteries

H2SO4

ldquooil of vitriolrdquo

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 16: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Nitric Acid HNO3

Nitric acid stains proteins yellow (like your skin)

Uses make explosives fertilizers rubber plastics dyes and pharmaceuticals

HNO3

ldquoaqua fortisrdquo

O

OO

N H

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 17: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Hydrochloric Acid HCl

The stomach produces HCl to aid in the digestion of food

Uses For lsquopicklingrsquo iron and steelPickling is the immersion of metals in acid solution to removesurface impurities

A dilute solution of HCl is called muriatic acid (available in many hardwarestores) Muriatic acid is commonly used to adjust pH in swimming pools and in the cleaning of masonry

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 18: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 19: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Relative Strengths of Acids and Bases

perchloric HClO4

hydrogen chloride HClnitric HNO3

sulfuric H2SO4

hydronium ion H3O+

hydrogen sulfate ion HSO4-

phosphoric H3PO4

acetic HC2H3O2

carbonic H2CO3

hydrogen sulfide H2Sammonium ion NH4

+

hydrogen carbonate ion HCO3-

water H2Oammonia NH3

hydrogen H2

Dec

reas

ing

Aci

d S

tren

gth

perchlorate ion ClO4-

chloride ion Cl-

nitrate ion NO3-

hydrogen sulfate ion HSO4-

water H2Osulfate ion SO4

2-

dihydrogen phosphate ion H2PO4-

acetate ion C2H3O2-

hydrogen carbonate ion HCO3-

hydro sulfide ion HS-

ammonia NH3

carbonate ion CO32-

hydroxide ion OH-

amide ion NH2-

hydride ion H-

Dec

reas

ing

Bas

e S

tren

gth

Acid Formula Conjugate base Formula

Metcalfe Williams Catska Modern Chemistry 1966 page 229 acid conjugate base + H+

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 20: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids)

The prefix hydro- is used to represent hydrogen followed by the nameof the nonmetal with its ending replaced by the suffix ndashic and the wordacid added

Examples

HCl

HBr

The name of this compound would be hydrogen chloride if it was NOT dissolved in water

Hydrochloric acid

Hydrobromic acid

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 21: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Naming Simple Chemical Compounds

Ionic (metal and nonmetal) Covalent (2 nonmetals)

Metal

Formsonly onepositive

ion

Formsmore than

one positiveion

Nonmetal

Use the name of element

Use elementname followed

by a Romannumeral to

show the charge

Firstnonmetal

Secondnonmetal

Beforeelement name

use a prefixto matchsubscript

Use a prefixbefore

element name and end with ide

SingleNegative

Ion

Polyatomic Ion

Use the nameof the

element butend with ide

Use thename of

polyatomicion (ate or

Ite)

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 22: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Naming Ternary Compounds from Oxyacids

The following table lists the most common families of oxy acids

one moreoxygen atom

mostldquocommonrdquo

one lessoxygen

two lessoxygen

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

H2SO4

sulfuric acid

H2SO3

sulfurous acid

H3PO4

phosphoric acid

H3PO3

phosphorous acid

H3PO2

hypophosphorous acid

HNO3

nitric acid

HNO2

nitrous acid

(HNO)2

hyponitrous acid

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 23: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Oxyacids Oxysalts If you replace hydrogen with a metal you have formed an oxysaltA salt is a compound consisting of a metal and a non-metal If thesalt consists of a metal a nonmetal and oxygen it is called anoxysalt NaClO4 sodium perchlorate is an oxysalt

HClO4

perchloric acid

HClO3

chloric acid

HClO2

chlorous acid

HClOhypochlorous acid

NaClO4

sodium perchlorate

NaClO3

sodium chlorate

NaClO2

sodium chlorite

NaClOsodium hypochlorite

OXYACID OXYSALT

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 24: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

ACID SALT

per stem ic changes to per stem ate

stem ic changes to stem ate

stem ous changes to stem ite

hyper stem ous changes to hypo stem ite

HClO3 + Na1+ NaClO3 + H1+

acid cation salt

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 25: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Arrhenius Acids and BasesAcids release hydrogen ions in waterBases release hydroxide ions in water

An acid is a substance that produces hydronium ions H3O+ when dissolved in water

Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pairA Lewis base is a substance than can donate (and share) an electron pair

Lewis Acid

Broslashnsted-Lowry DefinitionsA Broslashnsted-Lowry acid is a proton donor it donates a hydrogen ion H+A Broslashnsted-Lowry base is a proton acceptor it accepts a hydrogen ion H+

Broslashnsted-LowryArrhenius

acids

Acid Definitions

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 26: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid ndash Base Systems

Type Acid Base

Arrhenius H+ or H3O + producer

OH - producer

Broslashnsted-Lowry

Proton (H +) donor

Proton (H +) acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 27: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Arrhenius Bases and Their Properties

According to the definition of Arrhenius a

Base - a substance whose water solution yields

Are NaOH and NH3 considered to be Arrhenius bases

1) Bases are electrolytes

Dissociation equation for NH3

NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)

Dissociation equation for NaOH

NaOH(s) Na1+(aq) + OH1-(aq)

2) Bases cause indicators to turn a characteristic color

3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

YES

4) Water solutions of bases tasted bitter and feel slippery

hydroxide ions (OH-) as the only negative ions

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 28: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Neutralization

Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)base acid salt water

Some neutralization reactions

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 29: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

NeutralizationNeutralization

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basicbull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 30: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

bull Salts can be neutral acidic or basic

bull Neutralization does not mean pH = 7

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 31: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Salt Formation

NaOH HCl

strongbase

strongacid

salt of a strong base and a strong acidNaCl

NaOH HC2H3O2

strongbase

weakacid

salt of a strong base and a weak acidNaC2H3O2

Note that in each case H-OH (water) is formed

NaOH + HCl NaCl + H2O

NaOH + HC2H3O2 NaC2H3O2 + H2O

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 32: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Salt Formation

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH3HC2H3O2

weakbase

weakacid

salt of a weak base and a weak acidNH4 C2H3O2

Note that in each case H-OH (water) is also formed

NH4OH H2SO4

NH4OH + H2SO4 (NH4)2SO4 + H2O

NH4OH + HC2H3O2 NH4C2H3O2 + H2O

NH4OH

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 33: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

NH3H2SO4

weakbase

strongacid

salt of a weak base and a strong acid(NH4) 2 SO4

NH4OH H2SO4

ammonium ion

NH4+

hydroxide ion

OH-

1+ 1-

NH4+ OH-

1+ 1-

sulfuric acid

(NH4)2SO4

HOH

1+

HOH

1+

sulfate ion

2 NH4OH + H2SO4 (NH4)2SO4 + 2 HOH

waterammonium sulfate

2-

H2SO4

2 NH4OH + H2SO4 (NH4)2SO4 + 2 H2O

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 34: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

phosphoric acid ammonium hydroxide ammonium phosphate

Reactions that produce salt acid + base salt + water

H3PO4 NH4OH (NH4)3PO4 H2O

nitric acid magnesium hydroxide magnesium nitrateHNO3 Mg(OH)2 Mg(NO3)2 H2O

carbonic acid potassium hydroxide potassium carbonateH2CO3 KOH K2CO3 H2O

acetic acid aluminum hydroxide aluminum acetateHC2H3O2 Al(OH)3 Al(C2H3O2)3 H2O

perchloric acid barium hydroxide barium perchlorateHClO4 Ba(OH)2 Ba(ClO4)2 H2O

+ +and yields and water

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 35: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Broslashnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton

Base = any substance that accepts a proton

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 36: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Broslashnsted-Lowry Acids and Bases

(acid)

H2O

(base)

NH3

d+d-1+

+

ammonium ion

NH4+

1-

hydroxide ion

OH-

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 37: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

DefinitionsDefinitions

Broslashnsted-Lowry

HCl + H2O Clndash + H3O+

bull Acids are proton (H+) donors bull Bases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 38: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3ndash

CBCAAB

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH O

O

ON

Base Acid

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 39: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

DefinitionsDefinitions

Amphoteric - can be an acid or a base

NH3 + H2O NH4+ + OH-

CA CBB A

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

H

H

OH

N

Base Acid

H

H

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 40: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 41: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 42: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

DefinitionsDefinitions

Lewisbull Acids are electron pair acceptors bull Bases are electron pair donors

Lewis base

Lewis acid

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 43: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH Scale

Acid Base

0

7

14

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 515

[H+] pH

10-14 14

10-13 13

10-12 12

10-11 11

10-10 10

10-9 9

10-8 8

10-7 7

10-6 6

10-5 5

10-4 4

10-3 3

10-2 2

10-1 1

100 0

1 M NaOH

Ammonia(householdcleaner)

BloodPure waterMilk

VinegarLemon juiceStomach acid

1 M HCl

Aci

dic

N

eutr

al

Bas

ic

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 44: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH of Common Substances

Timberlake Chemistry 7th Edition page 335

10 MHCl0

gastricjuice16

vinegar28

carbonated beverage30

orange35

apple juice38

tomato42

lemonjuice22 coffee

50

bread55

soil55

potato58

urine60

milk64

water (pure)70

drinking water72

blood74

detergents80 - 90

bile80

seawater85

milk of magnesia105

ammonia110

bleach120

10 MNaOH(lye)140

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 45: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH of Common Substance

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH 01 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white seawaterHuman blood tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 46: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid ndash Base Concentrations

pH = 3

pH = 7

pH = 11

OH-

H3O+OH-

OH-H3O+

H3O+

[H3O+] = [OH-] [H3O+] gt [OH-] [H3O+] lt [OH-]

acidicsolution

neutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

sL

)

10-14

10-7

10-1

Timberlake Chemistry 7th Edition page 332

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 47: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH

pH = -log [H1+]

Kelter Carr Scott Chemistry A World of Choices 1999 page 285

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 48: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH Calculations

pH

pOH

[H3O+]

[OH-]

pH + pOH = 14

pH = -log[H3O+]

[H3O+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

[H3O+] [OH-] = 1 x10-14

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 49: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH = - log [H+]

pH = 46

pH = - log [H+]

46 = - log [H+]

- 46 = log [H+]

- 46 = log [H+]

Given

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 251x10-5 M

You can check your answer by working backwards

pH = - log [H+]

pH = - log [251x10-5 M]

pH = 46

Recall [H+] = [H3O+]

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 50: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

003 M 003 M 003 M

pH = - log [H+]

pH = - log [003M]

pH = 152eg HCl HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

03 M 06 M 03 M

pH = - log [H+]

pH = - log [06M]

pH = 022eg H2SO4

Given pH = 21

find [H3PO4]

assume 100 dissociation

eg H3PO4

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

M x M

pH =

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 51: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Given pH = 21

find [H3PO4]

assume 100 dissociation

H3PO4(aq) 3 H1+(aq) + PO43-(aq)

X M 000794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

21 = - log [H+]

- 21 = log [H+]

2nd log - 21 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-21

[H+] = 000794 M

[H+] = 794 x10-3 M794 x10-3 M

Step 3) Calculate [H3PO4] concentration

Note coefficients (13) for (H3PO4 H+)

794 x10-3 M3

= 000265 M H3PO4

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 52: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

How many grams of magnesium hydroxide are needed to add to 500 mL of H2O to yield a pH of 100

Step 1) Write out the dissociation of magnesium hydroxide Mg2+ OH1-

Mg(OH)2Mg(OH)2(aq) Mg2+(aq) 2 OH1-(aq)+

Step 2) Calculate the pOH pH + pOH = 14100 + pOH = 14

pOH = 40

Step 3) Calculate the [OH1-] pOH = - log [OH1-]

[OH1-] = 10-OH

[OH1-] = 1 x10-4 M

1 x10-4 M05 x10-4 M5 x10-5 M

Step 4) Solve for moles of Mg(OH)2

L

mol M

L 05

molx M x105 5- x = 25 x 10-5 mol Mg(OH)2

Step 5) Solve for grams of Mg(OH)2

x g Mg(OH)2 = 25 x 10-5 mol Mg(OH)2 1 mol Mg(OH)2

= 000145 g Mg(OH)2

58 g Mg(OH)2

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 53: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

[ CaO ] shift

[ CO2 ] shift

-- shift eggshells are thinner

In a chickenhellip CaO + CO2

CaCO3

(eggshells)

In summer [ CO2 ] in a chickenrsquos blood due to panting

How could we increase eggshell thickness in summer

-- give chickens carbonated water

-- put CaO additives in chicken feed

-- air condition the chicken house TOO much $$$

-- pump CO2 gas into the chicken house

would kill all the chickens

I wish I had sweat glands

>
>

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 54: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

LeChatelierrsquos PrincipleN2 + 3 H2 2 NH3 + heat

Raising the temperaturehelliphellipfavors the endothermic reaction (the reverse reaction) in which the rise in temperature is counteracted by the absorption of heat

Increasing the pressurehelliphellipfavors the forward reaction in which 4 mol of gas molecules is converted to 2 mol

Decreasing the concentrationof NH3hellip

hellipfavors the forward reaction in order to replace the NH3 that has been removed

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532 Animation by Raymond ChangAll rights reserved

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 55: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Equilibrium Expression

322

23

eqHN

NHK

N2 + 3 H2 2 NH3 + heat

Dorin Demmin Gabel Chemistry The Study of Matter 3rd Edition page 532

Haber Process

reactants

productsKeq

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 56: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

reversible reaction

H2SO4 2 H1+ + SO42ndash

Acid dissociation is a reversible reaction

Rate at whichR P

Rate at whichP R=

looks like nothing is happening howeverhellipsystem is dynamic NOT static

equilibrium

Reactant Product and P RReactant Product

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 57: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Remove NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo NH3helliphelliphelliphelliphelliphelliphellip

ldquo ldquo H2helliphelliphelliphelliphelliphelliphellip

Add more N2helliphelliphelliphelliphelliphelliphellip

Le Chatelierrsquos principle

N2(g) + 3 H2(g) 2

NH3(g)

Le Chatelierrsquos principle

Disturbance Equilibrium Shift

no shift

When a system at equilibrium is disturbed it shifts to a new equilibrium that counteracts the disturbance

Add a catalysthelliphelliphelliphelliphelliphelliphellip

Increase pressurehelliphelliphelliphelliphellipFritz Haber

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 58: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

shift to a new equilibrium

Then go insidehellip

shift to a new equilibrium

Light-Darkening Eyeglasses

AgCl + energy Ago + Clo

ldquoenergyrdquo

Go outsidehellip Sunlight more intense than inside light

GLASSES DARKEN

(clear) (dark)

ldquoenergyrdquo

GLASSES LIGHTEN

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 59: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Maintaining Blood pH

Acid entering the blood stream Carbon dioxide is exhaled

HCO31- + H+ H2CO3 H2O + CO2

Bicarbonate ion circulates in the blood stream where it is in equilibrium with H+ and OH-In the lungs bicarbonate ions combine with a hydrogen ion and lose a water molecule to form carbon dioxide which is exhaled

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 60: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Alkalosis

If our breathing becomes too fast (hyperventilation)hellip

Carbon dioxide is removed from the blood too quickly

This accelerates the rate of degradation of carbonic acid into carbon dioxide and waterThe lower level of carbonic acid encourages the combination of hydrogen ions andbicarbonate ions to make more carbonic acid The final result is a fall in blood H1+

levels that raises blood pH which can result in over-excitability or death

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 61: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acidosis

If breathing becomes too slow (hypoventilation)hellip

hellipfree up acid pH of blood drops with associated health risks such as depressionof the central nervous system or death

The normal pH of blood is between 72 ndash 74 This pH is maintained by the bicarbonate ion and other buffers

Kelter Carr Scott Chemistry A World of Choices 1999 page 291

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 62: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

H+ A - H+ A - HA

A - H+ A - H+ A ndash

H+ A - H+ A - H+

A - HA H+ A -

H+ A - H+ A - H+

HA HA HA HA

HA HA HA

H+ A - HA HA

HA HA H + A ndash

HA H + A ndash HA HA

H+ A- H+ A- H+ A- H+ A- HAA- H+ A- H+ A- H+ A- H+ A -

H+ A- HA H+ A- H+ A- H+ A-

A- H+ A- H+ A- H+ A- H+ A- H+ H+ A - H + A - H + A - HA H + A -

A- H+ A- H+ A- H+ A- H+ Andash

H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A- H+ A-

HA A- H+ A- H+ A- H+ A- H+

HA HA H+ A- HA HA HA HA HA HA HA HA H+ A- H+ A- HA HA HA HA HA

HA HA H+ A- HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA HA H+

A- HA HA H+ A- HA HA HA HA HA HA HA H+ A- HA HA HA

DILUTECONCENTRATED

ST

RO

NG

WE

AK

STRONG ACIDS

Dissociate nearly 100

HA H1+ + A-

WEAK ACIDS

Dissociate very little

HA H1+ + A-

Acids Concentration vs Strength

>
>

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 63: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Comparison of Strong and Weak Acids

Type of acid HA Reversibilityof reaction

Ka value Ions existing when acidHA dissociates in H2O

StrongNot

reversibleKa value very large

H+ and A- onlyNo HA present

Weak reversible Ka is small H+ A- and HA

HA(aq) + H2O(l) H3O+(aq) + A-(aq)

The equilibrium expression for the reaction is

Ka = [H3O+] [A-]

[HA]Note H3O+ = H+

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 64: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Strong vs Weak Acid

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 65: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Concentrated vs Dilute

03 M HCl

20 M HCl

120 M HCl

100 M CH3COOHDilute strong acid

Concentrated strong acidOR Dilute strong acid

Concentrated strong acid

Concentrated weak acid

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 66: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Naming Acids

_________ ide(chloride Cl1-)

_________ite(chlorite ClO2

-)(hypochlorite ClO-)

_________ ate(chlorate ClO3

-)(perchlorate ClO4

-)

Hydro____ ic acid(hydrochloric acid HCl)

_________ic acid(chloric acid HClO3)

(perchloric acid HClO4)

______ous acid(chlorous acid HClO2)

(hypochlorous acid HClO)

Anion Acid

add H+

add H+

add H+

ions

ions

ions

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 67: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

[H3O+]

Equilibrium and pH Calculations

HA + H2O H3O+ + A-

Weak acid

HA + H2O H3O+ + A-

Strong acid

acid-dissociationconstant calculations

Ka = [A-] [H3O+]

[HA]

[HA] = [H3O+]

+

pH0 7 14

antilog(-pH)

-log [H3O+] [OH-]-

1 x 10-14

[OH-]=

1 x 10-14

[H3O+]=

Tocci Viehland Holt Chemistry Visualizing Matter 1996 page 525

HA H+ + A-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 68: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Strengths of Conjugate Acid-Base Pairs

strong medium weak very weak

Acid strength increases

HCl H2SO4 HNO3 H3O+ HSO4- H3PO4 HC2H3O2 H2CO3 H2S H2PO4

- NH4+ HCO3

- HPO42- H2O

negligible very weak weak medium strong

Base strength increases

Cl- HSO4- NO3 H2O SO4

2- H2PO4- C2H3O2

- HCO3- HS- HPO4

2- NH3 CO32- PO4

3- OH-

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 69: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Kw = [H3O+][OH-]

1 x 10-14 = [H3O+][OH-]

Keqequilibrium constant

Kwwater dissociation

constant

Kaacid dissociation

constant

Kbbase dissociation

constant

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 70: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

H+ + NH3 NH4+NH4

+ H+ + NH3

acid CB

CAbase

HA H+ + A-

HA H+ + A-

strong acid

weak acid

01 M 01 M 01 M

01 M M

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 71: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Conjugate Acid Strength Very

strong

Strong

Weak

Veryweak

Relativeacid

strength

Relativeacid

strength

Relativeconjugate

basestrength

Relativeconjugate

basestrength

Veryweak

Very strong

Weak

Strong

HA H+ + A-

pKa = [H+] [A-] [HA]

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 508

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 72: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

[C] [D]

[Products]

A(g) + 2 B(g) 3 C(g) + D(g)

Weak Acids (pKa)

Weak Acids ndash dissociate incompletely (~20)Strong Acids ndash dissociate completely (~100)

Equilibrium constant (Keq) =

Keq = LeChatelierrsquos Principle (lu-SHAT-el-YAYrsquos)

[Reactants]

[A][B]

3

2

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 73: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

H+(aq) + C2H3O2

1-(aq)CH3COOH(aq)HC2H3O2(aq)

[Reactant]

[Product]Equilibrium constant Keq =

= Ka = Acid dissociation constant

Ka = 18 x 10-5 25 oC for acetic acid

[H+][C2H3O21-]

[HC2H3O2]

[H+][C2H3O21-]

[HC2H3O2]Ka =

[H+][C2H3O21-]

[HC2H3O2]=18 x 10-5

Assume we begin with 01 M acetic acid

[01 M ]

[X ][X ]

X2 = 18 x 10-6 M

= 134 x 10-3 M[H+]X

pH = -log[H+]

pH = -log[134 x10-3]

pH = 287

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 74: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

HC2H3O2 H+ + C2H3O2

1-

HCl H+ + Cl1- very large

HNO3 H+ + NO3

1- very large

H2SO4 H+ + HSO41- large

18 x 10-5

H2S H+ + HS1- 95 x 10-8

Ionization Constants for Acids

Ka

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 75: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

H2SO4 2 H+ + SO42- in dilute solutionsoccurs ~100

H2SO4 H+ + HSO4

1- amp HSO41- H+ +

SO42-

One gram of concentrated sulfuric acid (H2SO4) is diluted to a 10 dm3 volume

with water What is the molar concentration of the hydrogen ion in this solution What is the pH

x mol H2SO4 = 1 g H2SO4

Solution)First determine the number of moles of H2SO4

Sample 1)

= 0010 mol H2SO4

OVERALL

pH = - log [H+]

pH = 169

0010 M 0020 M

substitute into equation pH = - log [0020 M]

98 g H2SO4

1 mol H2SO4

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 76: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

A volume of 571 cm3 of pure acetic acid HC2H3O2 is diluted with water at

25 oC to form a solution with a volume of 10 dm3

Step 2) Find the number of moles of acid

x mol acetic acid = 600 g HC2H3O2 = 010 mol acetic acid (in 1 L)

M = 01 molar HC2H3O2

Step 3) Find the [H+]Ka =

Step 1) Find the mass of the acidMass of acid = density of acid x volume of acid

= 105 gcm3 x 571 cm3

= 600 g

Molarity M = mol LSubstitute into equation M = 010 mol 1 L

What is the molar concentration of the hydrogen ion H+ in this solution (The density of pure acetic acid is 105 gcm3)

(From the formula of acetic acid you can calculate that the molar mass of acetic acid is 60 g mol)

60 g HC2H3O2

1 mol HC2H3O2

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 77: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Step 3) Find the [H+]

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

18 x 10-5 =

Ka = 18 x 10-5 25 oC for acetic acid

H C H O

HC H O

12 3 2

2 3 2

[ ][ ]

[ ]

Ka =

Substitute into equation ]OH[HC

[x][x] 10 x 18

232

5-

]M [010x

10 x 182

5-

x2 = 18 x 10-6 M

x = 13 x 10-3 molar = [H+]

HC2H3O2 H+ + C2H3O2

1-

01 M

pH = - log[H+]

pH = - log [13 x10-3 M]

pH = 29

01 Mweak acid

How do the concentrations of H+ and C2H3O2

1- compare

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 78: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Moles of Acid used to make 1 L of solution

H+ pH

0010 mol H2SO4 Strong acid

0100 mol HC2H3O2 Weak acid

Note although the sulfuric acid is 10x less concentrated than the acetic acidhellipit produces gt 10x more H+

H+ ConcentrationshellipStrong vs Weak Acid

pH = - log[H+]

17

29

00200 M

00013 M

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 79: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

1a) What is the molar hydrogen ion concentration in a 200 dm3 solution

of hydrogen chloride in which 365 g of HCl is dissolved 1b) pH

2a) What is the molar concentration of hydrogen ions in a solution containing 320 g of HNO3 in 250 cm3 of solution

2b) pH

3a) An acetic acid solution is 025 M What is its molar concentration of

hydrogen ions3b) pH

4) A solution of acetic acid contains 120 g of HC2H3O2 in 500 cm3 of solution What is the molar concentration of hydrogen ions

1a) 00500 M 2a) 0203 M 3a) 21 x 10-3 M 4) 27 x 10-3 M1b) pH = 13 2b) pH = 07 3b) pH = 27

Practice Problems

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 80: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Weak Acids

Cyanic acid is a weak monoprotic acid If the pH of 0150 M cyanic acid is 232calculate Ka for cyanic acid

HCN(aq) H+(aq) + CN1-(aq)

H3O+(aq)

0150 M 48 x 10-3 M

Ka = [Products]

[Reactants]Ka =

[H3O+]

[HCN]

[CN1-]

Ka = [48 x 10-3 M]

[0150 M]

[CN1-][48 x 10-3 M]

Ka = 154 x 10-4

48 x 10-3 M

pH = -log[H3O+]

10-pH = [H3O+]

10-232 = [H3O+]

48 x10-3 M = [H3O+]

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 81: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid Dissociation

Kelter Carr Scott Chemistry A World of Choices 1999 page 280

HCl

Conjugate baseAcid

Conjugate pair

+

1-

Cl

H

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 82: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Conjugate Acid-Base Pairs

HCl + H2O H3O+ + Cl-

acid base

base acid

conjugates

conjugates

HCl + H2O H3O+ + Cl-

acid base CA CB

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 83: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Conjugate Acid-Base Pairs

NH3 + H2O NH41+ + OH-

base acid

acid base

conjugates

conjugates

base acid CA CB

NH3 + H2O NH41+ + OH-

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 84: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Water is Amphoteric

base acid CA CB

NH3 + H2O NH41+ + OH-

HCl + H2O H3O+ + Cl-

acid base CA CB

Amphoteric or Amphiprotic substances

Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 85: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Amphoteric

1-

+ +

sulfuric acidH2SO4

waterH2O

hydrogen sulfateion

HSO4-

hydronium ion

A substance that can act as either an acid or a base

H3O+

1+

1-

+ +

sulfate ion

SO42-

water

H2O

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

2-

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 86: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

1-

+ +

1+

sulfuric acid

H2SO4

water

H2O

hydrogen sulfateion

HSO4-

hydronium ion

H3O+

(HSO4- as a base)

Amphoteric

A substance that can act as either an acid or a base

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 87: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Amphoteric

A substance that can act as either an acid or a base

1-

+

hydrogen sulfateion

HSO4-

hydroxide ion

OH-

1-

+

sulfate ion

SO42-

water

H2O

2-

(HSO4- as an acid)

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 88: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Conjugate Acid-Base Pairs

HC2H3O2 + H2O H3O1+ + C2H3O2-

acid1 base1

base2 acid2

conjugates

conjugates

acid base CA CB

HC2H3O2 + H2O H3O1+ + C2H3O2-

The reaction proceeds in the direction such that the stronger acid donates its proton to the stronger base

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 89: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Litmus Paper

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 90: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 91: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Copyright copy 2007 Pearson Benjamin Cummings All rights reserved

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 92: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Desired Features of Sensors

pH paper 1904

Detection limit

Low deflection

High sensitivity

High selectivity

Wide dynamic range

Simple to use

Cost-effective

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 93: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Bromthymol blue indicator would be used in titrating a strong acid with a strong base

Phenolpthalein indicator would be used in titrating a weak acid with a strong base

Methyl orange indicator would be used in titrating a strong acid with a weak base

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 94: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

1 2 3 4 5 6 7 8 9 10 11 12Indicator

Phenolphthalein

Methyl Red

Orange IV

Colorless Pink Red

Red Orange Yellow

Orange Peach Yellow

pH

phenolphthalein methyl red methyl orange

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 95: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Red Cabbage IndicatorCopyright copy 2007 Pearson Benjamin Cummings All rights reserved

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 96: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Phenolphthalein Indicator

Colorless = Acidic pH

Pink = Basic pH

H+

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 97: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

23

24

How to read a buret volume

2345 mL

(not 2455 mL)

2455 mL

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 98: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration

bull Titrationndash Analytical method in which

a standard solution is used to determine the concentration of an unknown solution

standard solution

unknown solutionCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 99: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

bull Equivalence point (endpoint)ndash Point at which equal amounts of

H3O+ and OH- have been added

ndash Determined byhellipbull indicator color change

Titration

bull dramatic change in pH

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 100: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration M of HCl 300 mL of 20 M of NaOH

If it requires 105 mL of M HCl to titrate 300 mL of 20 M NaOH to its endpointwhat is the concentration of the HCl

M1V1 = M2V2

M V = M V H+ H+ OH- OH-HCl(aq) H+(aq) + Cl-(aq)

01 M 01 M 01 M

H2SO4(aq) 2 H+(aq) + SO42-(aq)

01 M ldquo02 Mrdquo 01 M

proper term is Normality (N)

M V n = M V n H+ H+ OH- OH-

Al(OH)3(aq) Al3+(aq) + 3 OH-(aq)

105 mL

HCl must be ~ __x more concentratedthan the NaOH

6

(x M)(105 mL) = (20 M)(300 mL)

X = 57 M

300 mL of NaOH with bromthymol blue indicator

muriatic acid

sunnyside

01 molar H2SO4 is 02 normal

105 mL of HCl

Endpoint of titration is reachedhellipcolor change

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 101: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration

moles H3O+ = moles OH-

MV n = MV nM MolarityV volumen of H+ ions in the acid

or OH- ions in the baseCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 102: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Solutionof NaOHSolutionof KOH

Solution

of H2SO4

500 mL

Titration

425 mL of 13M KOH are required to neutralize 500 mL of H2SO4

Find the molarity of H2SO4

H3O+

M = V = 500 mL n = 2

OH-

M = 13M V = 425 mL n = 1

MV = MVM(500mL)(2)

=(13M)(425mL)(1)

M = 055M H2SO4

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 103: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid-Base Titration

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 104: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Calibration Curve

Acid (mL)

Bas

e (m

L)010 M HCl M NaOH

000 mL100 mL200 mL400 mL900 mL1700 mL2700 mL4200 mL

100 mL100 mL200 mL500 mL800 mL100 mL150 mL

1) Create calibration curve of six data points2) Using [HCl] determine concentration of NH3

3) Determine vinegar concentration using [NaOH] determined earlier in lab

Solutionof NaOHSolutionof NaOH

Solution

of HCl

5 mL

Data Table

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 105: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration Curve

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 106: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Calibration Curve

Acid (mL)

Bas

e (m

L)

pH

endpoint

equivalence point

indicator

base

7

pink

- changes color to indicate pH change

eg phenolphthalein is colorless in acid and pink in basic solution

PiratehelliprdquoWalk the plankrdquo once in water shark eats and water changes to pink color

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 107: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration Curve

Zumdahl Zumdahl DeCoste World of Chemistry 2002 page 527

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 108: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

Acid-Base Titrations

Adding NaOH from the buret to hydrochloric acid in the flask a strong acid In the beginning the pH increases very slowlyAdding additional NaOH is added pH rises as the equivalence point is approachedAdditional NaOH is added pH increases and then levels off asNaOH is added beyond the equivalence point

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 109: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Strong Acid With a Strong Base

000 1001000 1372000 1952200 2192400 2702500 7002600 11302800 11753000 11964000 12365000 1252

NaOH added (mL) pH

Titration Data

Solutionof NaOHSolutionof NaOH

Solutionof HCl H+

H+ H+

H+

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

OH-

OH-OH-

OH-

25 mL

phenolphthalein - colorless

phenolphthalein - pink

Bromthymol blue is best indicator pH change 60 - 76

Yellow Blue

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 110: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration of a Strong Acid With a Strong Base

equivalence point

140

120

100

80

60

40

20

0000 100 200 300

pH

Volume of 0500 M NaOH added(mL)

Color changemethyl violet

Color changebromphenol blue

Color changebromthymol blue

Color changephenolpthalein

Color changealizarin yellow R

(2000 mL of 0500 M HCl by 0500 M NaOH)

Hill Petrucci General Chemistry An Integrated Approach 2nd Edition page 680

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 111: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M NaOH added(mL)

Titration of a Weak Acid Witha Strong Base

000 289 500 4141000 4571250 4741500 4922000 5352400 6122500 8722600 11303000 11964000 1236

NaOH added (mL) pH

Titration Data

Titration of a Weak Acid With a Strong Base

Phenolphthalein is best indicator pH change 80 - 96

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 112: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

equivalence point

140

120

100

80

60

40

20

0000 100 200 300 400

pH

Volume of 0100 M HCl added(mL)

Titration of a Weak Base With a Strong Acid

000 11241000 9912000 9473000 8934000 8614500 8304700 7924800 7704900 7475000 5855100 334

HCl added (mL) pH

Titration Data

Titration of a Weak Base With a Strong Acid

500

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 113: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

7 What is the pH of a solution made by dissolving 25 g NaOH in 400 mL water

Determine number of moles of NaOH

x mol NaOH = 25 g NaOH

NaOH g 40NaOH mol 1

00625 mol NaOH

Calculate the molarity of the solution

Lmol M

L 04NaOH mol 00625

[Recall 1000 mL = 1 L]

MNaOH = 015625 molar

NaOH Na1+ + OH1-

015625 molar 015625 molar015625 molar

pOH = -log [OH-]

pOH = -log [015625 M]

pOH = 08

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [015625 M]

[H+] = 64 x 10-14 M

pH = -log [H+]

pH = 132 pH = -log [64 x 10-14 M]08 + pH = 14

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 114: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

What volume of 05 M HCl is required to titrate 100 mL of 30 M Ca(OH)2

x = 600 mL of 05 M HCl

HCl H1+ + Cl1-

03 mol 03 mol03 mol

HCl + Ca(OH)2 CaCl2 + HOH 22

x mL05 M

100 mL30 M

M1V1 = M2V2

(05 M) (x mL) = (30 M) (100 mL)

x = 1200 mL of 05 M HCl

M1V1 = M2V2

(05 M) (x mL) = (60 M) (100 mL)

Ca(OH)2 Ca2+ + 2OH1-

03 mol 06 mol03 mol

M

mol

L

HClmolHCl = M x L

mol = (05 M)(06 L)

mol = 03 mol HCl

Ca(OH)2

mol = (30 M)(01 L)

mol = 03 mol Ca(OH)2

mol = M x LCa(OH)2

[H+] = [OH-]

60 M

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 115: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

6 100 grams vinegar

M

mol

LNaOH

molNaOH = M x L

mol = (0150 M)(00654 L)

mol = 000981 mol NaOH

titrated with 6540 mL of 0150 M NaOH(acetic acid + water)

moles NaOHmoles HC2H3O2 =

therefore you have 000981 mol HC2H3O2

B)

A)

x g HC2H3O2 = 000981 mol HC2H3O2

232

232

OHHC mol 1OHHC g 60

059 g HC2H3O2

C) = 100 x wholepart

= 100 x vinegar g 100

acidacetic g 059

= 59 acetic acid

Commercial vinegar is sold as 3 - 5 acetic acid

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 116: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

49 mL 02 M HCl + 50 mL 02 M NaOH

A) molHCl = M L

molHCl = (02 M) (0049 L)

molHCl = 00098 mol

B) molNaOH = M L

molNaOH = (02 M) (005 L)

molNaOH = 0010 mol

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by combining 49 mL of 02 M HCl with 50 mL of 02 M NaOH

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

HCl + NaOH H2O + NaCl

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 117: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

M

mol

L

49 mL 02 M HCl

50 mL 02 M NaOH

99 mL H2O1 mL of 02 M NaOH

0010 mol OH1-

00098 mol H1+-

00002 mol OH1-ldquonetrdquo

1) What is the pH of a solution made by adding 1mL of 02 M NaOH with 99 mL H2O

NaOH Na1+ + OH1-

Calculate the molarity of the solution

[Recall 1000 mL = 1 L]

MNaOH = 0002020 molar

NaOH Na1+ + OH1-

0002020 molar 0002020 molar0002020 molar

pOH = -log [OH-]

pOH = -log [0002020 M]

pOH = 27

pOH + pH = 14

or kW = [H+] [OH-]

1 x 10-14 = [H+] [0002020 M]

[H+] = 495 x 10-12 M

pH = -log [H+]

pH = 113 pH = -log [495 x 10-12 M]27 + pH = 14

M = molL

M = 00002 mol NaOH

00099 L

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 118: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Carboxylic Acid

HC2H3O2

CH3COOH

C2H4O2

R - COOH

H C C

H

H

O

O

H

carboxylic acid

H+

= acetic acid

1-

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 119: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Lactic Acid

H3C C CO2H

H

OH

Lactic acidC3H6O3

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 120: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Titration

M NaOH10 M HCl titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

M NaOH10 M H2SO4 titrate with

100 mL 200 mL

M1 V1 = M2 V2

(10 M)(100 mL) = (x M)(200 mL)

X = 05 M NaOH

20 M H1+

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 121: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

Acid Basevinegar ammonia

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solution

M

mol

L

NaOH

molNaOH = M x L

mol = (0130 M)(00196 L)

mol = 0002548 mol NaOH

moles NaOHmoles HC2H3O2 =

therefore you have 0002548 mol HC2H3O2

B)

A)

x g HC2H3O2 = 0002548 mol HC2H3O2

232

232

OHHC mol 1

OHHC g 600153 g HC2H3O2

C) = 100 x whole

part

= 100 x vinegar g 30

acidacetic g 01529

= 51 acetic acid Commercial vinegar is sold

as 3 - 5 acetic acid

Calculate molarity (M) of acetic acid M1V1 = M2V2Calculate acetic acid in vinegar = partwhole x100

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 122: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Calibration CurveVinegar Ammonia 1 mL 3 mL 5 mL 10 mL 15 mL

vinegar

amm

oni

a

Using 3 mL vinegarhellip

titrate with 0130 M NaOH solutionCalculate molarity (M) of acetic acid M1V1 = M2V2

M1 V1 = M2 V2

(Macetic acid)(30 mL) = (0130 MNaOH )(196 mL)

Macetic acid = 08493 molar

It required 196 mL of NaOH to reach the endpoint

Acid Basevinegar ammonia

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 123: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

HCl

H2SO4

H3PO4

HNO3

CH3COOH

HF

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Nitric acid

Acetic acid

Hydrofluoric acid

stomach acid pickling metal

battery acid 1 selling chemical

food flavoring

fertilizer explosives

vinegar

etch glass

NaOH Ca(OH)2 NH4OH

sodium hydroxide calcium hydroxide ammonium hydroxide

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 124: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH scale0

7

14

acid

neutral

base

[H+] = [OH-]

Soren Sorenson developed pH scale

pOH = -log [OH-]

kW = [H+] [OH-]

pH = -log [H+]

pH + pOH = 14

(alkalinity)

Arnold Beckman invented the pH meter

H+ + H2O H3O+

proton hydronium ion

kw = 1 x 10-14

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 125: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Concentrated vs Dilute

Concentration Molarity molality Normality

M = molL m =

molkg

H2SO4 2 H1+ + SO42-

3 M ldquo6 Mrdquo

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 126: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Strong Weak Acid

Strong HA H+ + A- (~100 dissociation)

Weak HA H+ + A- (~20 dissociation)

Ka = [Product][Reactant]

acid dissociation constant

Ka

08 H3PO4 3H+ + PO43-

00021 HF H+ + F-

H2A 2 H+ + A-

Ka = [H+]2 [A-]

[H2A]

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 127: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Acid + Base Salt + Water

How would you make calcium sulfate in the lab

+ CaSO4

ACID

Sour taste litmus red

Arrhenius ndash H+ as only ion in water

Broslashnsted-Lowry ndash proton donor

BASE

bitter taste litmus blue

Arrhenius ndash OH- as only ion in water

Broslashnsted-Lowry ndash proton acceptor

H2SO4 Ca(OH)2 + 2 H2O

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 128: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

phenolphthalein colorless pinkacid baseweak strong

bromthymol blue yellow blue

acid basestrong strong

universal indicator R O Y G B I V

pH 4 7 12

litmus paper amp pH paper

Indicators

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 129: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Buffers - salts of weak acids and weak bases that maintain a pH

LeChatelierrsquos Principle- acidosis amp alkalosis (bicarbonate ion acts as buffer)- darkening glasses- egg shells thinner in summer (warm)

eg Aspirin (acetyl salicylic acid) vs Bufferinlow pH upsets stomach

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 130: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Amino Acids ndash Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 131: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Water ndash Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

NH

HH

NH

HH

H 1+

NH

H

1-

H+ lose H+

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 132: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Water ndash Also Amphiprotic

H2OOH1- H3O1+

hydroxide water hydronium ion

H+ lose H+

Amphiprotic ndash Act as an acid (proton donor) or base (proton acceptor)

O2-

H+

H+

-dd+

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 133: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Range and Color Changes of SomeCommon Acid-Base Indicators

Indicators

pH Scale1 2 3 4 5 6 7 8 9 10 11 12 13 14

Methyl orange red 31 ndash 44 yellow

Methyl red red 44 62 yellow

Bromthymol blue yellow 62 76 blue

Neutral red red 68 80 yellow

Phenolphthalein colorless 80 100 red colorless beyond 130

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 134: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Neutralization of Bug Bites

Wasp - stings with base

(neutralize with lemon juice or vinegar)

Red Ant - bites with acid

(neutralize with baking soda)

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 135: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

StrengthStrength

Strong AcidBasebull 100 ionized in waterbull strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 136: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

StrengthStrength

Weak AcidBasebull does not ionize completelybull weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 137: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Ionization of WaterIonization of Water

H2O + H2O H3O+ + OH-

Kw = [H3O+][OH-] = 10 10-

14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 138: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Why is pure water pH = 7Why is pure water pH = 7

1 in 500000000 water molecules will autoionize

H2O + H2O H3O+ + OH1-

This yields a hydronium ion concentration of 1 x 10-7 M H3O+ per liter of solution

pH = -log[H3O+]pH = -log[1 x 10-7] or pH = 7

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 139: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

HH

OHH

HH

HHO

HH1-

1+

HHO

HH

HH

O HH

HH

OHH

HH O

HH

OHH

HH

HH

O

HH

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 140: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

Ionization of WaterIonization of Water

Find the hydroxide ion concentration of 30 10-2 M HCl

[H3O+][OH-] = 10 10-14

[30 10-2][OH-] = 10 10-14

[OH-] = 33 10-13 M

Acidic or basicAcidicCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 141: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH = -log[H3O+]

pH ScalepH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pouvoir hydrogegravene (Fr)ldquohydrogen powerrdquo

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 142: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH ScalepH Scale

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 143: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH ScalepH Scale

What is the pH of 0050 M HNO3

pH = -log[H3O+]

pH = -log[0050]

pH = 13

Acidic or basicAcidic

Courtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)
Page 144: Acids, Bases, and Salts You should be able to Understand the acid-base theories of Arrhenius, Brønsted-Lowry, and Lewis. Identify strong acids and.

pH ScalepH Scale

What is the molarity of HBr in a solution that has a pOH of 96

pH + pOH = 14

pH + 96 = 14

pH = 44

Acidic

pH = -log[H3O+]

44 = -log[H3O+]

-44 = log[H3O+]

[H3O+] = 40 10-5 M HBrCourtesy Christy Johannesson wwwnisdnetcommunicationsartspageschem

  • Acids Bases and Salts
  • Slide 2
  • Slide 3
  • Acid vs Base
  • Properties
  • Common Acids and Bases
  • Acid + Base Salt + Water
  • Acid-Base Neutralization
  • Formation of Sulfuric Acid
  • Slide 11
  • Slide 12
  • Common Acids
  • Common Acids (2)
  • Formation of Hydronium Ions
  • Sulfuric Acid H2SO4
  • Nitric Acid HNO3
  • Hydrochloric Acid HCl
  • Common Bases
  • Relative Strengths of Acids and Bases
  • Binary Hydrogen Compounds of Nonmetals When Dissolved in Water
  • Naming Simple Chemical Compounds
  • Naming Ternary Compounds from Oxyacids
  • Oxyacids Oxysalts
  • ACID SALT
  • Acid Definitions
  • Acid ndash Base Systems
  • Arrhenius Bases and Their Properties
  • Neutralization
  • Neutralization (2)
  • Slide 31
  • Salt Formation
  • Salt Formation (2)
  • Slide 34
  • Reactions that produce salt
  • Broslashnsted-Lowry Acids and Bases
  • Broslashnsted-Lowry Acids and Bases (2)
  • Definitions
  • Definitions (2)
  • Definitions (3)
  • Definitions (4)
  • Definitions (5)
  • Definitions (6)
  • pH Scale (2)
  • pH of Common Substances
  • pH of Common Substance
  • Acid ndash Base Concentrations
  • pH
  • pH Calculations
  • pH = - log [H+]
  • Acid Dissociation
  • Slide 53
  • Slide 54
  • Slide 55
  • LeChatelierrsquos Principle
  • Equilibrium Expression
  • Slide 58
  • Le Chatelierrsquos principle
  • Light-Darkening Eyeglasses
  • Maintaining Blood pH
  • Alkalosis
  • Acidosis
  • Slide 64
  • Comparison of Strong and Weak Acids
  • Strong vs Weak Acid
  • Concentrated vs Dilute
  • Naming Acids
  • Equilibrium and pH Calculations
  • Strengths of Conjugate Acid-Base Pairs
  • Slide 71
  • Slide 72
  • Conjugate Acid Strength
  • Weak Acids (pKa)
  • Slide 75
  • Slide 76
  • Slide 77
  • Slide 78
  • Slide 79
  • Slide 80
  • Slide 81
  • Weak Acids
  • Acid Dissociation (2)
  • Conjugate Acid-Base Pairs
  • Conjugate Acid-Base Pairs (2)
  • Water is Amphoteric
  • Amphoteric
  • Amphoteric (2)
  • Amphoteric (3)
  • Conjugate Acid-Base Pairs (3)
  • Litmus Paper
  • pH Paper
  • Slide 93
  • Slide 94
  • Slide 95
  • Slide 96
  • Red Cabbage Indicator
  • Phenolphthalein Indicator
  • How to read a buret volume
  • Titration
  • Titration (2)
  • Titration (3)
  • Titration (4)
  • Titration (5)
  • Acid-Base Titration
  • Slide 110
  • Titration Curve
  • Slide 112
  • Titration Curve (2)
  • Acid-Base Titrations
  • Slide 115
  • Titration of a Strong Acid With a Strong Base
  • Titration of a Weak Acid With a Strong Base
  • Titration of a Weak Base With a Strong Acid
  • Slide 119
  • Slide 120
  • Slide 121
  • Slide 122
  • Slide 123
  • Carboxylic Acid
  • Lactic Acid
  • Titration (10)
  • Slide 127
  • Slide 128
  • Slide 129
  • Slide 130
  • Slide 131
  • Slide 132
  • Slide 133
  • Indicators
  • Slide 135
  • Slide 136
  • Slide 137
  • Slide 138
  • Slide 139
  • Neutralization of Bug Bites
  • Strength
  • Strength (2)
  • Ionization of Water
  • Why is pure water pH = 7
  • Slide 145
  • Ionization of Water (2)
  • pH Scale (3)
  • pH Scale (4)
  • pH Scale (5)
  • pH Scale (6)

Acids and Bases pH and Titrations. Overview Acid – Base Concepts Arrhenius Brønsted – Lowry Lewis Acid and Base Strengths Relative Strengths.

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OpenStax Chemistry 2e 14.1: Brønsted-Lowry Acids and Bases

Chapter 15 Acids and Bases. Copyright © Cengage Learning. All rights reserved.15 | 2 Acid–Base Concepts 1.Arrhenius Concept of Acids and Bases 2.Brønsted–Lowry.

Chapter 15 Acids and Bases. Copyright © Cengage Learning. All rights reserved.15 | 2 Acid–Base Concepts 1.Arrhenius Concept of Acids and Bases 2.Brønsted–Lowry.

The Brønsted-Lowry Theory of Acids Two important theories have been developed to explain the properties of acids, bases, and salts. These are the Arrhenius.

The Brønsted-Lowry Theory of Acids Two important theories have been developed to explain the properties of acids, bases, and salts. These are the Arrhenius.

Arrhenius Definition of Acids and Bases

Arrhenius Definition of Acids and Bases

Acid-Base Theories n OBJECTIVES: –Compare and contrast acids and bases as defined by the theories of: a) Arrhenius, b) Brønsted-Lowry, and c) Lewis.

Acid-Base Theories n OBJECTIVES: –Compare and contrast acids and bases as defined by the theories of: a) Arrhenius, b) Brønsted-Lowry, and c) Lewis.

Chapter 3 Acids and Bases - faculty.fiu.edufaculty.fiu.edu/~kellerl/SolomonsLKChapter3.pdfReactions of BrØnsted-Lowry Acids and Bases • A BrØnsted-Lowry acid base reaction results

Chapter 3 Acids and Bases - faculty.fiu.edufaculty.fiu.edu/~kellerl/SolomonsLKChapter3.pdfReactions of BrØnsted-Lowry Acids and Bases • A BrØnsted-Lowry acid base reaction results

I Arrhenius and Brønsted-Lowry Acids and Bases · PDF fileI – Arrhenius and Brønsted-Lowry Acids and Bases A) ... The equilibrium of a Bronsted-Lowry acid-base reaction depends

I Arrhenius and Brønsted-Lowry Acids and Bases · PDF fileI – Arrhenius and Brønsted-Lowry Acids and Bases A) ... The equilibrium of a Bronsted-Lowry acid-base reaction depends

AP Chemistry: Acids, Bases, and Salts...2017/02/24  · 1 AP Chemistry: Acids, Bases, and Salts Unit Objectives 1. Understand the acid-base theories of Arrhenius, Brønsted-Lowry,

AP Chemistry: Acids, Bases, and Salts...2017/02/24  · 1 AP Chemistry: Acids, Bases, and Salts Unit Objectives 1. Understand the acid-base theories of Arrhenius, Brønsted-Lowry,

Acid/Base Equilibria Chapter 16. Models of Acids and Bases Arrhenius Concept: Acids produce H + in solution, bases produce OH ion. Brønsted-Lowry: Acids.

Acid/Base Equilibria Chapter 16. Models of Acids and Bases Arrhenius Concept: Acids produce H + in solution, bases produce OH ion. Brønsted-Lowry: Acids.

10.1 SECTION Arrhenius Acids and Bases - Wikispaces - Acids & Bases.pdf... · Acidic substances Basic substances 10.1SECTION Arrhenius Acids and Bases Key Terms Arrhenius theory of

10.1 SECTION Arrhenius Acids and Bases - Wikispaces - Acids & Bases.pdf... · Acidic substances Basic substances 10.1SECTION Arrhenius Acids and Bases Key Terms Arrhenius theory of

Acids and Bases Three major ways to define acids and bases introduced by Lewis, Brønsted and Arrhenius. They differ in the role of water Arrhenius and.

Acids and Bases Three major ways to define acids and bases introduced by Lewis, Brønsted and Arrhenius. They differ in the role of water Arrhenius and.

Acids & Bases Svante Arrhenius (1887)

Acids & Bases Svante Arrhenius (1887)

Section 4.3 Acid-Base Reactions. Acids: Substances that increase the concentration of H + when dissolved in water (Arrhenius). Proton donors (Brønsted–Lowry).

Section 4.3 Acid-Base Reactions. Acids: Substances that increase the concentration of H + when dissolved in water (Arrhenius). Proton donors (Brønsted–Lowry).