Solubility Solubility ChartChart

At higher temperatures:•Most solids become more soluble•Most gases become less soluble.

Therefore…Therefore…Solids tend to dissolve best when:

o Heatedo Stirredo Ground into small particles

Liquids tend to dissolve best when:

o The solution is coldo Pressure is high

““Like Dissolves Like”Like Dissolves Like”

Fats Benzene

Steroids Hexane

Waxes ToluenePolar and ionic solutes dissolve best in polar solvents

Nonpolar solutes dissolve best in nonpolar solvents

Inorganic Salts Water

Sugars Small alcohols

Acetic acid

Saturation of SolutionsSaturation of Solutions A solution that contains the maximum amount A solution that contains the maximum amount

of solute that may be dissolved under existing of solute that may be dissolved under existing conditions is conditions is saturatedsaturated..

A solution that contains less solute than a A solution that contains less solute than a saturated solution under existing conditions is saturated solution under existing conditions is unsaturatedunsaturated..

A solution that contains more dissolved solute A solution that contains more dissolved solute than a saturated solution under the same than a saturated solution under the same conditions is conditions is supersaturatedsupersaturated..

http://www.youtube.com/watch?v=tkHQ2e6BYbIhttp://www.youtube.com/watch?v=tkHQ2e6BYbI

Ionic SolutionsIonic Solutions

Ionic Compounds in WaterIonic Compounds in WaterDissociationDissociation – the separation of ions that – the separation of ions that occur when an ionic compound dissolves.occur when an ionic compound dissolves.

NaCl NaCl (aq) (aq) → →

NaNa1+1+ + Cl + Cl1-1-

PHET SimulationPHET Simulation

http://phet.colorado.edu/en/simulation/soluble-saltshttp://phet.colorado.edu/en/simulation/soluble-salts

http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf

DissociationDissociation

Example: dissociation of sodium Example: dissociation of sodium chloridechloride

HH22OO

NaCl (s) → Na NaCl (s) → Na 1+ (aq)1+ (aq) + Cl + Cl 1-(aq)1-(aq)

Example: dissociation of calcium Example: dissociation of calcium chloridechloride

HH22OO

CaClCaCl22 (s)(s) → Ca → Ca 2+ (aq)2+ (aq) + 2 Cl + 2 Cl 1-(aq)1-(aq)

Concentration of SolutionsConcentration of SolutionsVocabularyVocabulary

Solution:Solution:A liquid (usually) with something dissolved inside.A liquid (usually) with something dissolved inside.Solute:Solute:A substance dissolved in a solvent liquid. (lesser A substance dissolved in a solvent liquid. (lesser

ingredient)ingredient)Solvent:Solvent:The liquid that dissolves or holds the solute. The liquid that dissolves or holds the solute.

(greater ingredient)(greater ingredient)Concentration:Concentration:The strength of the solution measured as the ratio The strength of the solution measured as the ratio

of the amount of solute vs amount of solventof the amount of solute vs amount of solvent(%, mg/L, mmol/L)(%, mg/L, mmol/L)

MolarityMolarityMolarity is the ratio of moles of solute Molarity is the ratio of moles of solute

to liters of solution (mostly solvent).to liters of solution (mostly solvent).MM = mol/L = mol/L

*Mole Chart 3*Mole Chart 3

Demo – Mixing a solution of KMnODemo – Mixing a solution of KMnO44

Solving Solving MM = mol/L with algebra for: = mol/L with algebra for:Moles: Moles: mol = L* mol = L* MMLiters:Liters: L = mol/L = mol/MMGrams:Grams: L* L* MM = mol x mw = g = mol x mw = g

Particles(atoms or

Molecules)

Mole Chart (3)Mole Chart (3)

MolesMass (g) X ÷

÷ xMW

A# 6.02x106.02x102323

Volume ofGas at STP

(L)

÷ x 22.4L

SolutionConcentration

(M)

M=mol/L

DilutionsDilutionsDemo: Dilute KMnODemo: Dilute KMnO44 solution from Molarity solution from Molarity

Demo. Calculate new concentration.Demo. Calculate new concentration.

1.1. CC11VV11=C=C22VV2 2

2.2. C – concentration, V - volumeC – concentration, V - volume

3.3. The concentration decreases The concentration decreases proportionally to the increase in volume.proportionally to the increase in volume.

4.4. CC11vv11 = c = c22VV22

5.5. VV22 = v = v11 + H + H22O = Total Final VolumeO = Total Final Volume

Asmt: 15-2 all, Get a head start on Beer’s Asmt: 15-2 all, Get a head start on Beer’s Law LabLaw Lab

Acids & BasesAcids & Bases

pH Balance?pH Balance?

Acid – Base VocabularyAcid – Base VocabularyAcidAcidBaseBaseIndicatorIndicatorNeutralizationNeutralizationHydronium ionHydronium ionAmphotericAmphotericConjugate acidConjugate acidConjugate baseConjugate baseDissociationDissociation

pH pH BufferBufferTitrationTitrationEquivalence pointEquivalence point

Video: Elements of Chemistry -Video: Elements of Chemistry -Acids, Bases & SaltsAcids, Bases & Salts

Household Acids & Bases LabHousehold Acids & Bases LabSolutionSolution Blue litmusBlue litmus Red litmusRed litmus Universal Universal

IndicatorIndicatorpHpH

VinegarVinegar

AmmoniaAmmonia

Lemon juiceLemon juice

Soft drinkSoft drink

Drain Drain cleanercleaner

DetergentDetergent

Baking sodaBaking soda

Prune JuicePrune Juice

Berry JuiceBerry Juice

Mentos & PopMentos & Pop

http://http://www.stevespanglerscience.com/www.stevespanglerscience.com/experiment/00000109experiment/00000109

Properties of Acids vs BasesProperties of Acids vs BasesAcids:Acids:

Taste Sour – vinegar!Taste Sour – vinegar!

Feel like water but sting Feel like water but sting cuts.cuts.

Turn litmus red.Turn litmus red.

Have pH lower than 7Have pH lower than 7

React with active metals to React with active metals to form explosive Hform explosive H22 gas. gas.

Act as electrolytes to Act as electrolytes to conduct electricity.conduct electricity.

Neutralize bases!Neutralize bases!

Bases:Bases:Taste bitter – soap!Taste bitter – soap!Feel slippery.Feel slippery.Turn litmus blue.Turn litmus blue.Have pH higher than 7Have pH higher than 7Don’t react with most Don’t react with most

metals.metals.

Act as electrolytes to Act as electrolytes to conduct electricity.conduct electricity.

Neutralize acids!Neutralize acids!

Acids React with Active Acids React with Active MetalsMetals

Acids react with active metals to form salts and hydrogen gas.

Mg + 2HCl MgCl2 + H2(g)

Acids React with CarbonatesAcids React with Carbonates

2HC2H3O2 + Na2CO3

2 NaC2H3O2 + H2O + CO2

Products of NeutralizationProducts of NeutralizationHCl + NaOH H2SO4 + Ca(OH)2 HNO3 + KOH The products of neutralization are always a ______ and _______.

NaCl + H2O

CaSO4 + 2 H2O

KNO3 + H2O

salt water

Acids Neutralize BasesAcids Neutralize Bases

HCl + NaOH NaCl + H2O

Neutralization reactions ALWAYS produce a salt and water.

Effects of Acid Rain on MarbleEffects of Acid Rain on Marble(calcium (calcium carbonatecarbonate))

George Washington:BEFORE

George Washington:AFTER

Examples of BasesExamples of Bases

Sodium hydroxide (lye), NaOHSodium hydroxide (lye), NaOH Potassium hydroxide, KOHPotassium hydroxide, KOH Magnesium hydroxide, Mg(OH)Magnesium hydroxide, Mg(OH)22

Calcium hydroxide (lime), Ca(OH)Calcium hydroxide (lime), Ca(OH)22

Bases Effect IndicatorsBases Effect Indicators

Red litmus paper turns blue in contact with a base. Phenolphthale

in turns purple in a base.

Bases Bases have a pH have a pH

greater greater than 7than 7

Bases Neutralize Bases Neutralize AcidsAcids

Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl.

2 HCl + Mg(OH)2

MgCl2 + 2 H2O

Acids you must know:Acids you must know:

Strong Acids Weak Acids

Hydrochloric acid, HCl

Nitric acid, HNO3

Sulfuric acid, H2SO4 Phosphoric acid, H3PO4

Acetic acid, HC2H3O2

Carbonic acid, H2CO3

Naming Acids – Correspond to Naming Acids – Correspond to Anion SufficesAnion Suffices

A. -ide ionA. -ide ion

Ex: chloride, ClEx: chloride, Cl--

B. -ite ionB. -ite ion

Ex: sulfite, SOEx: sulfite, SO33-2-2

C. –ate ionC. –ate ion

Ex: phosphate, POEx: phosphate, PO44-3-3

A. Hydro___ic acidA. Hydro___ic acid

Ex: Hydrochloric acid, Ex: Hydrochloric acid, HClHCl

B. –ous acidB. –ous acid

Ex: sulfous acid, HEx: sulfous acid, H22SOSO33

C. –ic acidC. –ic acid

Ex: phosphoric acid, Ex: phosphoric acid, HH33POPO44

Write the Names & Formulas of Write the Names & Formulas of the following Acidsthe following Acids

1. HF 1. HF

2. H3PO3 2. H3PO3

3. H2SO4 3. H2SO4

4. HCl 4. HCl

5. HClO35. HClO3

6. HI6. HI

7. HNO2 7. HNO2

8. HC2H3O28. HC2H3O2

1. hydrobromic acid1. hydrobromic acid

2. nitric acid 2. nitric acid

3. hydrosulfuric acid3. hydrosulfuric acid

4. hydrocyanic acid4. hydrocyanic acid

5. sulfurous acid5. sulfurous acid

6. boric acid 6. boric acid

7. chlorous acid7. chlorous acid

8. carbonic acid8. carbonic acid

Sulfuric AcidSulfuric Acid Highest volume production Highest volume production

of any chemical in the U.S.of any chemical in the U.S. Used in the production of Used in the production of

paperpaper Used in production of Used in production of

fertilizersfertilizers Used in petroleum refiningUsed in petroleum refining

Nitric AcidNitric AcidUsed in the production of Used in the production of fertilizersfertilizers

Used in the production of Used in the production of explosivesexplosives

Nitric acid is a volatile Nitric acid is a volatile acid – its reactive acid – its reactive components evaporate components evaporate easilyeasily

Stains proteins (including Stains proteins (including skin!)skin!)

Hydrochloric AcidHydrochloric AcidUsed in the pickling of Used in the pickling of steelsteel

Used to purify Used to purify magnesium from sea magnesium from sea waterwater

Part of gastric juice, it Part of gastric juice, it aids in the digestion of aids in the digestion of proteinprotein

Sold commercially as Sold commercially as “Muriatic acid”“Muriatic acid”

Phosphoric AcidPhosphoric Acid

o A flavoring agent in A flavoring agent in sodassodas

o Used in the Used in the manufacture of manufacture of detergentsdetergents

o Used in the Used in the manufacture of manufacture of fertilizersfertilizers

o NotNot a common a common laboratory reagentlaboratory reagent

Acetic AcidAcetic AcidUsed in the Used in the

manufacture of manufacture of plasticsplastics

Used in making Used in making pharmaceuticalspharmaceuticals

Acetic acid is the acid Acetic acid is the acid present in vinegarpresent in vinegar

Carbonic AcidCarbonic Acid

•Removes carbon dioxide from the body.

•Mediates the carbon dioxide levels in the atmosphere.

Arrhenius Acids & BasesArrhenius Acids & BasesAcids:Acids:

Release HRelease H++ ions by ions by dissociation. dissociation.

Example: HClExample: HCl

Combine HCombine H++ with with any negative ion any negative ion on your ion chart on your ion chart to form an acid.to form an acid.

Examples: ???Examples: ???

Bases:Bases:

Release OHRelease OH-- ions ions by dissociation.by dissociation.

Example: NaOHExample: NaOH

Combine OHCombine OH-- with with any metal on the any metal on the periodic table to periodic table to form a base.form a base.

Examples: ???Examples: ???

Arrhenius DefinitionArrhenius DefinitionAn acid is a substance that dissociates in An acid is a substance that dissociates in water to produce hydrogen ions.water to produce hydrogen ions.

HClHCl(l) (l) + H+ H22OO (l) (l) → H→ H1+1+ (aq) (aq) + Cl + Cl1-1-

(aq) (aq)

HH22SOSO4 (l)4 (l) + H + H22OO (l) (l) ↔↔ H H1+1+ (aq) (aq) + HSO + HSO44

1-1-(aq)(aq)

- Must be dissolved in water.Must be dissolved in water.- Does not explain why the covalent Does not explain why the covalent

bonds are broken.bonds are broken.

Arrhenius DefinitionArrhenius DefinitionAn base is a substance that dissociates in An base is a substance that dissociates in water to produce hydroxide ions (OHwater to produce hydroxide ions (OH1-1-).).

NaOH NaOH → Na→ Na1+1+ (aq) (aq) + OH + OH1-1-

(aq) (aq)

Ba(OH)Ba(OH)22 ↔↔ Ba Ba2+2+ (aq) (aq) + 2 OH + 2 OH1-1-

(aq) (aq)

Does not explain compounds with Does not explain compounds with characteristics of bases characteristics of bases –– NH NH33

Arrhenius ExplanationsArrhenius Explanations

H+ provides the sour taste & stings.H+ provides the sour taste & stings.

OH- the bitter taste & is slippery.OH- the bitter taste & is slippery.

Dissociation of both acids & bases Dissociation of both acids & bases produces dissolved ions which act as produces dissolved ions which act as electrolytes.electrolytes.

Neutralization occurs when H+ & OH- Neutralization occurs when H+ & OH- combine to form H2O. The left overs combine to form H2O. The left overs produce a salt like NaCl.produce a salt like NaCl.

Bronsted-Lowry Acids & BasesBronsted-Lowry Acids & BasesAcids:Acids:

Donate H+ ions.Donate H+ ions.

Example: Acetic Example: Acetic acid & amino acids.acid & amino acids.

H+ ions are H+ ions are protons.protons.

Bases: Bases:

Accept H+ ions.Accept H+ ions.

Example: Example: Ammonia, NHAmmonia, NH33

All inclusive All inclusive including bases including bases ignored by ignored by Arrhenius.Arrhenius.

Acids are Proton DonorsAcids are Proton Donors

Monoprotic acidsDiprotic acids Triprotic acids

HCl

HC2H3O2

HNO3

H2SO4

H2CO3

H3PO4

Bronsted-Lowry DefinitionBronsted-Lowry DefinitionAn acid is any substance that can An acid is any substance that can donate Hdonate H++ ions. ions.

HClHCl(g) (g) + H+ H22OO (l) (l) → H→ H1+1+ (aq) (aq) + Cl + Cl1-1-

(aq) (aq)

A base is any substance that can accept A base is any substance that can accept HH++ ions. ions.

NHNH3 (g)3 (g) + H + H22O O (l)(l) → → NHNH44++ (aq)(aq) + OH + OH1- 1-

(aq)(aq)

Acid/Base DefinitionsAcid/Base Definitions Arrhenius ModelArrhenius Model

Acids produce hydrogen ions in Acids produce hydrogen ions in aqueous solutionsaqueous solutions

Bases produce hydroxide ions in Bases produce hydroxide ions in aqueous solutionsaqueous solutions

Bronsted-Lowry ModelBronsted-Lowry Model Acids are proton donorsAcids are proton donors Bases are proton acceptorsBases are proton acceptors

Lewis Acid ModelLewis Acid Model Acids are electron pair acceptorsAcids are electron pair acceptors Bases are electron pair donorsBases are electron pair donors

Conjugate Acids & BasesConjugate Acids & Bases

Acids release H+ & bases accept H+.Acids release H+ & bases accept H+.

Once an acid releases its H+ it Once an acid releases its H+ it becomes a base that can accept H+ becomes a base that can accept H+ & vice versa.& vice versa.

Examples:Examples:

HH22COCO33 vs HCO vs HCO33-1-1

NHNH33 vs NH vs NH44+1+1

HH22O vs HO vs H33OO+1+1

Conjugate acid-base pairsConjugate acid-base pairsThe acid that loses a HThe acid that loses a H++ ion becomes the ion becomes the

conjugate base. The base that gains conjugate base. The base that gains the Hthe H+ + ion becomes the conjugate acid.ion becomes the conjugate acid.

HClHCl(g) (g) + H+ H22OO (l) (l) → H→ H33OO1+1+ (aq) (aq) + Cl + Cl1-1-

(aq) (aq)

acid base conj conjacid base conj conj acidacid base base

NHNH3 (g)3 (g) + H + H22O O (l)(l) → → NHNH44++ (aq)(aq) + OH + OH1- 1-

(aq)(aq)

base acid conj conj base acid conj conj acidacid base base

Hydronium IonHydronium IonWater is amphoteric – it can act as both an Water is amphoteric – it can act as both an acid & a base.acid & a base.When water acts as a base, it forms the When water acts as a base, it forms the hydronium ion.hydronium ion.

HH22O + HO + H++ H H33OO++

H+ ions always bind to something.H+ ions always bind to something.When water acts as an acid it forms OH-.When water acts as an acid it forms OH-.

HH220 0 OH OH-- + H + H++

The fraction of water that normally The fraction of water that normally dissociates is 10dissociates is 10-7-7 M. A very small fraction! M. A very small fraction! 1/10million!1/10million!

WaterWaterWater as a molecule is Water as a molecule is unique because it is unique because it is amphoteric. This means amphoteric. This means that it can react as either that it can react as either an acid or a base.an acid or a base.

H2O + H2O H3O+ + OH-

Ionization of HCl and formation of Ionization of HCl and formation of hydronium ion, Hhydronium ion, H33OO++

H2O + HCl H3O+ + Cl-

Protondonor

Protonacceptor

Hydrogen ions are “protons”Hydrogen ions are “protons”

Proton exchange animation Proton exchange animation http://web.jjay.cuny.edu/~acarpi/NSC/7-ph.htm

Acid Base Simulation (pHET)Acid Base Simulation (pHET)

http://phet.colorado.edu/en/http://phet.colorado.edu/en/simulation/acid-base-solutionssimulation/acid-base-solutions

Acids Effect IndicatorsAcids Effect Indicators

Blue litmus paper turns red in contact with an acid.

Acids Acids Have a Have a pH less pH less than 7than 7

pH Measures the H+ ConcentrationpH Measures the H+ ConcentrationpH uses logs which are just powers of 10.pH uses logs which are just powers of 10.

pH measures the electric “potential” of pH measures the electric “potential” of H+ ions in a solution.H+ ions in a solution.

pH is calculated as the negative “power” pH is calculated as the negative “power” of 10 of the H+ ion concentration.of 10 of the H+ ion concentration.

The equation for pH is pH = -log[H+]The equation for pH is pH = -log[H+]

[brackets] mean concentration in [brackets] mean concentration in Molarity.Molarity.

pH 7 is neutral, above 7 is basic & below pH 7 is neutral, above 7 is basic & below 7 is acidic.7 is acidic.

Simple pH CalculationsSimple pH Calculations

AcidAcid3.33.31010-3.3-3.3.00047.00047

BaseBase12121010-12-12.0000000000.00000000000101

BaseBase991010-9-9.000000001.000000001

neutralneutral771010-7-7.0000001.0000001

AcidAcid551010-5-5.00001.00001

AcidAcid331010-3-3.001.001

Acid or Acid or Base?Base?

pHpHPower of Power of 1010

HH++ Molarity Molarity

[H+], [OH-], pH, pOH[H+], [OH-], pH, pOH

H2O H2O H H++ + OH + OH--

This reaction goes back & forth in a This reaction goes back & forth in a balanced equilibrium quantified as:balanced equilibrium quantified as:

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

When neutral each are equal:When neutral each are equal:

[H+] = 10[H+] = 10-7-7M = [OH-]M = [OH-]

pH =7, pOH =7pH =7, pOH =7

In general pH + pOH =14In general pH + pOH =14

pH = -log[H+], pOH = -log[OH-]pH = -log[H+], pOH = -log[OH-]

pH and pOH CalculationspH and pOH Calculations

H + O H -

pH pO H

[O H -] = 1 x 10 - 1 4

[H + ]

[H + ] = 1 x 10 - 1 4

[O H -]

p O H = 14 - p H

p H = 14 - p O H

pOH

= -l

og[O

H- ]

pH =

-log

[H+

]

[OH

- ] = 1

0-pO

H

[H+

] = 1

0-pH

pH HomeworkpH Homework

http://www.sciencegeek.net/Chemistry/taters/Unit8pH.htm

Write down questions as knowns & Write down questions as knowns & unknowns, show work and answers unknowns, show work and answers for questions 1-22for questions 1-22

1.1.Calculate the Calculate the pOH of a solution whose [OH1-] = 5.5 x 10-5 M.

2.2.Calculate the Calculate the pH of a solution whose [H3O+] = 9.87 x 10-7 M.

3.3.Calculate the Calculate the pOH of a solution whose [OH1-] = 9.5 x 10-2 M.

4.4.Calculate the Calculate the pH of a solution whose [H3O+] = 6.7 x 10-13 M.

pH = -log [H3O+] pOH = -log [OH1-]

1.1. Calculate the Calculate the [OH1-] of a solutions whose pOH = 8.9.

2.2. Calculate the Calculate the [H3O+] of a solution whose pH = 12.7.

3.3. Calculate the Calculate the [H3O+] of a solution whose pH = 3.2.

4.4. Calculate the Calculate the [OH1-] of a solution whose pH = 7.8.

5.Calculate the [H3O+] of a solution whose pOH = 4.78.

[H3O+] = 10-pH [OH1-] = 10-pOH

pH and pOH using pH and pOH using compoundscompounds

1.1.Determine the pH of a 0.0034 M Determine the pH of a 0.0034 M HNOHNO33 solution. solution.

2.2.Determine the pOH of a 4.3 x 10Determine the pOH of a 4.3 x 10-4-4 M M NaOH solution. NaOH solution.

3.3.Determine the pOH of a 0.0034 M Determine the pOH of a 0.0034 M HNOHNO33 solution. solution.

4.4.Determine the pH of a 4.5 x 10Determine the pH of a 4.5 x 10-11-11 M M NaOH solution.NaOH solution.

Chemistry Chemistry Chapter Chapter

1616

Acid-Base Acid-Base Titration Titration and pHand pH

Self-Ionization of WaterSelf-Ionization of Water

H2O + H2O H3O+ + OH-

Ion Concentration in WaterIon Concentration in Water

KKww – Ionization Constant for – Ionization Constant for

WaterWaterIn pure water at 25 C:

[H3O+] = 1 x 10-7 mol/L

[OH-] = 1 x 10-7 mol/L

Kw is a constant at 25 C:

Kw = [H3O+][OH-]

Kw = (1 x 10-7)(1 x 10-7) = 1 x 10-

14

H+, OH-, and pHH+, OH-, and pH

pH pH ScalScal

ee

Calculating pH, pOHCalculating pH, pOHpH = -log10(H3O+)

pOH = -log10(OH-)

Relationship between pH and Relationship between pH and pOHpOH pH + pOH = 14

Finding [HFinding [H33OO++], [OH], [OH--] from pH, pOH] from pH, pOH

[H3O+] = 10-pH

[OH-] = 10-pOH

pH pH + +

pOH pOH = = 1414

Measuring pH with wide-range Measuring pH with wide-range paperpaper

pH pH IndicatorIndicator

s s and theirand theirrangesranges

pH CalculationspH Calculations

http://proton.csudh.edu/lecture_help/phcalcs.html

ACID-BASE REACTIONSACID-BASE REACTIONSTitrationsTitrations

ACID-BASE REACTIONSACID-BASE REACTIONSTitrationsTitrations

HH22CC22OO4 (aq)4 (aq) + 2 NaOH + 2 NaOH (aq)(aq) ---> --->

acidacid basebase

NaNa22CC22OO44(aq) + 2 H(aq) + 2 H22O(liq)O(liq)

Carry out this reaction using aCarry out this reaction using a TITRATIONTITRATION..

Oxalic acid,Oxalic acid,

HH22CC22OO44

Setup for titrating an acid with a baseSetup for titrating an acid with a base

Titration CurvesTitration Curves

TitrationTitrationTitrationTitration1. Add solution from the 1. Add solution from the

buret.buret.2. Reagent (base) reacts 2. Reagent (base) reacts

with compound (acid) with compound (acid) in solution in the flask.in solution in the flask.

3.3. Indicator shows when Indicator shows when exact stoichiometric exact stoichiometric reaction has occurred. reaction has occurred. (Acid = Base)(Acid = Base)

This is called This is called NEUTRALIZATION.NEUTRALIZATION.

Titrations ProblemsTitrations ProblemsRemember: acid = BaseRemember: acid = Base(V(Vbasebase)(M)(Mbasebase) = (V) = (Vacidacid)(M)(Macidacid))

35.62 mL of NaOH is 35.62 mL of NaOH is neutralized with 25.2 mL of neutralized with 25.2 mL of 0.0998 M HCl by titration to an 0.0998 M HCl by titration to an equivalence point. What is the equivalence point. What is the concentration of the NaOH?concentration of the NaOH?

Titration CalculationsTitration Calculations

Strong Acids vs. Weak AcidsStrong Acids vs. Weak Acids

Strong acids are assumed to be 100% ionized in solution (good proton donors).

Weak acids are usually less than 5% ionized in solution (poor proton donors).

HCl

H2SO4 HNO3

H3PO4 HC2H3O2 Organic acids

Organic AcidsOrganic AcidsOrganic acids all contain the “carboxyl” group, sometimes several of them.

The carboxyl group is a poor proton donor, so ALL organic acids are weak acids.

Examples of Organic AcidsExamples of Organic Acids Citric acid in citrus fruitCitric acid in citrus fruit Malic acid in sour applesMalic acid in sour apples Deoxyribonucleic acid, DNADeoxyribonucleic acid, DNA Amino acids, the building blocks of Amino acids, the building blocks of

proteinprotein Lactic acid in sour milk and sore Lactic acid in sour milk and sore

musclesmuscles Butyric acid in rancid butterButyric acid in rancid butter

pH Quiz – Determine the pH of:pH Quiz – Determine the pH of:

1.1. A 4.63 x 10A 4.63 x 10-8-8M solution of HNO3.M solution of HNO3.

2.2. A 250L solution containing 4.3mol A 250L solution containing 4.3mol of HCl.of HCl.

3.3. A 750.0ml solution containing A 750.0ml solution containing 0.0046mol of NaOH.0.0046mol of NaOH.

4.4. A 8.9L solution of 0.65mol of A 8.9L solution of 0.65mol of H2SO4.H2SO4.

TitrationsTitrationsTitrations measure the concentration of Titrations measure the concentration of solutions by finding out the amount of a known solutions by finding out the amount of a known solution needed to neutralize an unknown solution needed to neutralize an unknown solution.solution.Neutralization occurs when Mol H+ = Mol of Neutralization occurs when Mol H+ = Mol of OH-OH-M = mol/L M = mol/L mol = L x M mol = L x M mol = M x Vmol = M x V

MMaaVVaa = M = MbbVVb b (a is for acid, b is for base)(a is for acid, b is for base)Some acids are diprotic or triprotic, some Some acids are diprotic or triprotic, some bases are multi-hydroxy.bases are multi-hydroxy.

AMAMaaVVaa = BM = BMbbVVb b

(A is for # of H+, B is for # of OH-)(A is for # of H+, B is for # of OH-)

Friday 6-11-04Friday 6-11-04Prep: Prep: 1.1. Litmus papers, droppers fill up bottles.Litmus papers, droppers fill up bottles.2.2. Graduation RehearsalGraduation RehearsalClassClass1.1. End of Year ScheduleEnd of Year Schedule2.2. Vocabulary AssignmentVocabulary Assignment3.3. Lab – pH of Household SubstancesLab – pH of Household Substances

– Predictions Predictions – Handling the pH probe & storage bottleHandling the pH probe & storage bottle– Litmus tests & universal indicatorLitmus tests & universal indicator

Equilibrium of Reversible ReactionsEquilibrium of Reversible ReactionsMany reactions may proceed in both the Many reactions may proceed in both the

forward & backward directions.forward & backward directions.Carbonated Water:Carbonated Water:

COCO2(g)2(g) + H + H22O O (l)(l) H H22COCO3(aq)3(aq)

Carbonate pop by adding COCarbonate pop by adding CO2(g)2(g) pressure. pressure.

COCO2(g)2(g) + H + H22O O (l)(l) H H22COCO3(aq)3(aq)

Pop goes flat when container is opened!Pop goes flat when container is opened!

COCO2(g)2(g) + H + H22O O (l)(l) H H22COCO3(aq)3(aq)

Example 2: pH of PopExample 2: pH of Pop

1) CO1) CO2(g)2(g) + H + H22O O (l)(l) H H22COCO3(aq)3(aq)

2)2)HH22COCO3(aq)3(aq) H H++(aq)(aq) + HCO + HCO33

--(aq)(aq)

What is the pH of pop?What is the pH of pop?

When it goes flat, what happens to the When it goes flat, what happens to the pH?pH?

Strong Acid DissociationStrong Acid Dissociation

Weak Acid DissociationWeak Acid Dissociation

Equilibrium RatiosEquilibrium RatiosxAxA(aq)(aq) + + yByB(aq)(aq) zCzC(aq)(aq)

Equilibrium Ratio (K) = products/reactantsEquilibrium Ratio (K) = products/reactants

KKeqeq = [C] = [C]z z / [A]/ [A]xx[B][B]yy Coefficients = exponents!Coefficients = exponents!

Carbonated Water Equilibrium Ratio?Carbonated Water Equilibrium Ratio?

Each reaction has a different equilibrium Each reaction has a different equilibrium ratio value.ratio value.

Large ratios favor the _________, while small Large ratios favor the _________, while small ratios favor the _________.ratios favor the _________.

pH of Household SubstancespH of Household Substances1.1. Make the following data table in your notebook. Make the following data table in your notebook. 2.2. Rank & predict pH of samples to be used: soda pop, Rank & predict pH of samples to be used: soda pop,

drain cleaner, vinegar, ammonia, lemon juice, drain cleaner, vinegar, ammonia, lemon juice, detergent, baking sodadetergent, baking soda

3.3. ½ fill a well in the plate for each sample.½ fill a well in the plate for each sample.4.4. Test with red litmus, blue litmus & then add 1 drop of Test with red litmus, blue litmus & then add 1 drop of

universal indicator to observe the color. Dispose universal indicator to observe the color. Dispose down sink.down sink.

5.5. pH Probe:pH Probe:– Cap stays on probe. Place storage bottle by faucet.Cap stays on probe. Place storage bottle by faucet.– Rinse probe with distilled water before each test. Rinse probe with distilled water before each test. – Place probe in each sample bottle. Place probe in each sample bottle. – Swirl sample around probe for 30 seconds.Swirl sample around probe for 30 seconds.– Record pH from top right corner of calculator.Record pH from top right corner of calculator.– Recap all bottles when not in use.Recap all bottles when not in use.

Titrations QuizTitrations Quiz1.1. If 20.00ml of acidic drain cleaner is If 20.00ml of acidic drain cleaner is

titrated completely by 18.02ml of titrated completely by 18.02ml of 0.100M NaOH, what is the acid’s 0.100M NaOH, what is the acid’s concentration?concentration?

2.2. A 25.1ml volume of KOH is titrated A 25.1ml volume of KOH is titrated with 43.2ml of 0.150M Hwith 43.2ml of 0.150M H22SOSO44. What . What is the molarity of the KOH?is the molarity of the KOH?

3.3. A volume of 34.0ml of 0.100M HA volume of 34.0ml of 0.100M H33POPO44 neutralizes 25.0ml of Ba(OH)neutralizes 25.0ml of Ba(OH)22. What . What is the concentration of the barium is the concentration of the barium hydroxide?hydroxide?

Vinegar Titration LabVinegar Titration LabAdd 10.0 ml of vinegar to the beaker. Add Add 10.0 ml of vinegar to the beaker. Add 4 drops of indicator B, phenolpthalein.4 drops of indicator B, phenolpthalein.Fill the buret with 1.00M NaOH. Record Fill the buret with 1.00M NaOH. Record the starting volume.the starting volume.Titrate until the mixture turns pink & stays Titrate until the mixture turns pink & stays pink. Use the minimum of drops.pink. Use the minimum of drops.Measure the final volume and determine Measure the final volume and determine the change in volume of the base.the change in volume of the base.Use AMaVa = BMbVb to determine the Use AMaVa = BMbVb to determine the molarity of the vinegar, HC2H3O2.molarity of the vinegar, HC2H3O2.

Conjugate Acids & BasesConjugate Acids & BasesAny acid that can release H+ can re-accept and Any acid that can release H+ can re-accept and bind it to varying degrees.bind it to varying degrees.Strong acids like HCl release essentially all H+ Strong acids like HCl release essentially all H+ ions. HCl ions. HCl H H++ + Cl + Cl--

Weak acids like in vinegar release a small Weak acids like in vinegar release a small percentage of H+ ions. Most remain bound.percentage of H+ ions. Most remain bound.

HCHC22HH33OO22 H H++ + C + C22HH33OO22--

Salts contain positive & negative ions.Salts contain positive & negative ions.Any negative ion has some capacity to bind with Any negative ion has some capacity to bind with H+ ions to act like a base. Examples: ???H+ ions to act like a base. Examples: ???Conjugates represent examples with or without Conjugates represent examples with or without H+ attached. Examples: ???H+ attached. Examples: ???