Today… Before Class: Grab a Lab Packet, Safety Goggles, and Apron Our Plan: Inquiry Lab Wrap Up...

Today… Before Class:

Grab a Lab Packet, Safety Goggles, and Apron Our Plan:

Inquiry LabWrap Up – Venn Diagram

Homework (Write in Planner): Inquiry Lab Due next class

Quiz Make Up Tomorrow ELORocket Lab Make Up Thursday ELO

Today… Turn in:

Acid/Base Lab if haven’t yet Grab YOUR LAST Calendar, Booklet, & WS Packet You need a TEXTBOOK today!

Our Plan: New Calendar Notes Stop the Process/Activity Notes – pH Worksheet #1

Homework (Write in Planner): Worksheet #1 Due next class

Chemistry Humor….

Properties of Acids & Bases

ACIDS BASES

Produce H3O+1 ions when dissolved in water

Produce OH-1 ions when dissolved in water


ACIDS BASES

Taste tart or sour

Taste Bitter


ACIDS BASES

Corrosive to body tissue

Feel Slippery


ACIDS BASES

Turn blue litmus red

Turn red litmus blue


ACIDS BASES

Metals react with acids to form hydrogen gas


ACIDS BASES

Electrolytes


ACIDS BASESChange

color of

indicator


ACIDS BASESReact together to

form water

& a salt

Nomenclature of Acids

HCl Hydrochloric Acid

HF Hydrofluoric Acid

HBr Hydrobromic Acid

HI Hydroiodic Acid

More Acids

HC2H3O2 Acetic Acid

H2SO4 Sulfuric Acid

HNO3 Nitric Acid

H2CO3 Carbonic Acid

H3PO4Phosphoric Acid

Nomenclature of Bases

Generally, bases are metal hydroxides, so name the metal + hydroxide

Examples:KOH – potassium hydroxideNaOH – sodium hydroxideLiOH – lithium hydroxide

Real Life Acids

VinegarAspirinVitamin C (orange juice)Soft Drinks (Coca Cola)Foods – Citrus Fruits,

Tomatoes

Real Life Acids

Stomach Acid (Bulimia)FertilizerCar Batteries Acne Face Washes

Real Life Bases

AntacidsDeodorantsPlasterLaxativesBaking Soda

Real Life Bases

Dish DetergentBody Wash (Soap)LyeOven & Drain CleanerBleach

STOP

Complete the Stop the Process Activity in your notes.

Strong Acids/Bases

Fight Club Videohttp://www.youtube.com/watch?v=mg3m

8wRVXWg

Hydrogen Ions in Water

Water molecules, like anything, are in constant, random motion

Occasionally the collisions between water molecules are energetic enough to transfer a hydrogen ion from one molecule to another


A water molecule that loses a hydrogen ion becomes a negatively charged hydroxide ion (OH-1)

A water molecule that gains a hydrogen ion becomes a positively charged hydronium ion (H3O+1)


The reaction in which water molecules produce ions is called the self-ionization of water.

2H2O ↔ H3O+1 + OH-1

The Ionization of Water

2H2O ↔ H3O+1 + OH-1

At equilibrium, only 1.0 x 10-7 moles of H3O+1 and OH-1 are formed (at room temperature). So the concentrations of H3O+1 and OH-1 in pure water are 1.0 x 10-7 M.


This means the concentrations of H3O+1 and OH-1 are equal in pure water.

Any aqueous solution in which [H3O+1] and [OH-1] are equal is called a neutral solution.


In any aqueous solution, the product of hydronium ions and hydroxide ions equals 1 x 10-14

[H3O+1] [OH-1] = Kw = 1 X 10-14

Brackets indicate concentrationKw represents the ion-product

constant of water

Acidic & Basic Solutions

Not all solutions are neutralIf the concentration of hydronium is

greater than hydroxide, the solution is ACIDIC

If the concentration of hydronium is less than hydroxide, the solution is BASIC (alkaline)

pH

The concentrations of [H3O+1] & [OH-1] can be very small, and expressing concentration in molarity can be a pain, so…

Soren Sorensen came up with the pH scale in 1909

The pH scale is from 0-14, 0 being very acidic and 14 being very basic

pH

French for pouvoir hydrogene, which means “hydrogen power”

Low pH = very acidicHigh pH = very basic 7 = Neutral

Calculating pH

To turn such small concentrations into a pH scale, it is necessary to use logarithms

Logarithms allow a large range of values to be conveniently expressed as small, nonexponential numbers.

Do you remember logarithms from math class?

Calculating pH

For example, log 103 = 3 and log 106 = 6. Although there is a range of three orders of magnitude (10 x 10 x 10 or 1000) between the numbers 103 and 106, the range of the log values is only 3!

Calculating pH (strong acids)

To calculate, use:pH = -log[H3O+1]

[H3O+1] = hydronium ion concentration

WHY?

This is because strong acids completely dissociate

This means that the molarity of the acid IS THE SAME AS the molarity of H3O+1

Neutral Water

For this reason, neutral water has a pH of 7!

pH = -log[1 x 10-7]pH = 7Try typing it in your calculator

Try it Out!

Complete the pH table in your Note Booklet using your calculator and the formula.

The Answers

pH 10-pH

0 1

1 0.1

2 0.01

3 0.001

4 0.0001

The Answers

pH 10-pH

5 0.00001

6 0.000001

7 0.0000001

8 0.00000001

9 0.000000001

The Answers

pH 10-pH

10 1 x 10-10

11 1 x 10-11

12 1 x 10-12

13 1 x 10-13

14 1 x 10-14

pH

The numbers in the column 10-pH that you found are the hydronium ion concentration

To calculate [H3O+1] = 10-pH

pOH

pOH is the same as pH, but instead of being a measure of the hydronium ion concentration, it is the measure of the hydroxide ion concentration

It is the exact opposite!

pOH

Low pOH = very basic (alkaline)

High pOH = very acidic7 = neutral

Calculating pH (strong acids)

To calculate, use:pOH = -log[OH-1][OH-1] = hydroxide ion concentration

WHY?

This is because strong bases completely dissociate

This means that the molarity of the base IS THE SAME AS the molarity of OH-1

pOH

To calculate [OH-1]: [OH-1] = 10-pOH

Combining pH and pOH

pH +pOH = 14

The Flow Chart

What is the pH if the [OH-1]is 3.8 x 10-4 M?

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Example

What is the pOH if the [H3O+1] is 6.2 x 10-1 M?

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Example

What is the [H3O+1] if the [OH-1] is 1.3 x 10-8 M?

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Try It Out

What is the pH if the [OH-1] is 3.80 x 10-4 M?

10.6

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Try It Out

What is the pOH if the [OH-1] is 6.8 x 10-

6 M?

5.2

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

STOP…Worksheet Time!

Complete Worksheet #1 for next class.

Wrap Up

Properties of Acids & Bases Review

Today… Turn in:

WS #1 & Get out NOTES & CALCULATOR Our Plan:

Review Activities (Properties, Conjugate Acid/Base, pH calculations)

Homework Help Quiz – pH calculations Notes Worksheet #2 Wrap Up – Go Fish

Homework (Write in Planner): Worksheet #2 Due next class

Review

Properties of Acids & Bases Review

Conjugate Acid/Base ActivityExample H3PO4

Homework Help

10 Green A solution of

strontium hydroxide with a pH of 11.4 is to be prepared. What mass of strontium hydroxide would be required to make 1.00 L of this solution?

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Homework Help

11Green/11 Yellow Calculate the pH of

a solution that contains 5.00 g of HNO3 in 2.00 L of solution.

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Homework Help

12 Green/9 Yellow A hydrochloric acid

solution has a pH of 1.70. What is the [H3O+1] in this solution? Considering that HCl is a strong acid, what is the HCl concentration of the solution.

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Homework Help

13 Green/10 Yellow What is the molarity

of a solution of the strong base Ca(OH)2 in a solution that has a pH of 10.80?

- log[H3O+1]

[H3O+1] [OH-1]

10-pOH

pH pOH

- log[OH-1]

10-pH

pH + pOH = 14

Your Turn to Review

Complete the table of pH values individually. Check your work with your neighbor. After completing the review, you will take a quiz that looks exactly the same with different numbers!

Review Answers

[H3O+1] pH pOH [OH-1]

0.079 M 1.1 13 1.3 x 10-13 M

4.0 x 10-8 M 7.4 6.6 2.6 x 10-7 M

2.0 x 10-5 M 4.7 9.3 5.0 x 10-10 M

3.5 x 10-3 M 2.5 12 1.0 x 10-12 M

pH of Weak Acids

We calculate the pH of weak acids differently because they partially dissociate

That means the concentration of the acid IS NOT the same as the [H3O+1]

pH of Weak Acids

We use something called the Ka (the acid ionization constant)

It has been determined by experiments and is different for each acid

Determining Ka

Ka = [Products]

[Reactants]

How the pH formula is derived

What is the pH of a solution of 0.1 M acetic acid if the Ka for acetic acid is 1.8 x 10-5?

CH3COOH + H2O↔ CH3COO-1 + H3O+1

0.1 M XXn/a


Ka = [Products] [Reactants]1.8x10-5= __x2___ 0.1Mx is the [H30+1], which is

what we need to find pH!


CH3COOH + H2O↔ CH3COO-1 + H3O+1

0.1 M n/a X X

(0.1M)1.8*10-5= x2 (0.1M)

0.1M

√ 1.8*10-6= √x2

1.3 x 10-3= x = [H3O+1]


Basically, we multiplied the Ka by the concentration of the acid and took the square root of it.

Thus, the equation:

Equation for pH weak acids

[H3O+1] = √ Ka [HA]

Once you find [H3O+1], solve for pH just like before!

Sample Problem

Find the pH of a 0.4 M acetic acid solution. Ka for acetic acid is 1.8 x 10-5.

Sample Problem

[H3O+1] = √ (0.4M)(1.8 x 10-5)

[H3O+1] = 0.00268

pH = -log [H3O+1]

pH = -log[0.00268]pH = 2.57

Try It Out!

Find the pOH of a 0.33M acetic acid solution. Ka for acetic acid is 1.8 x 10-5.

Try It Out!

[H3O+1] = √ (0.33M)(1.8 x 10-5)

[H3O+1] = 0.00243

pH = -log [H3O+1]

pH = -log[0.00243]pH = 2.61

Not Done Yet!

pH + pOH = 1414 – 2.61 = pOHpOH = 11.39

Let’s do a hard one from the WS

#4 on BOTHWhat is the concentration of citric acid if

the solution has a pH of 2.5? (0.012 M)

pH Practice Problems

Complete WS # 2 by next class!

Wrap Up

Go Fish Time!

Today… Turn in:

WS #2 Our Plan:

ReviewQuizNotes/Videos IndicatorMake SherbetGo Fish

Homework (Write in Planner):Nothing

Review

1. What is the [OH-1] of a 0.4 M strong acid solution? 2.5 x 10-14

2. What is the pOH of a 6 x 10-4 M solution of strong base? 3.22

3. What is the pH if the pOH is 2.9? 11.1

4. What is the pOH of a 0.8 M weak acid solution of acetic acid. Ka for acetic acid 1.8 x 10-5 M. 11.57

Acid – Base Demonstration

IndicatorsDefinition: Compounds

whose colors are sensitive to pH

Their color

changes as pH

changes

Indicators

Transition interval – the pH range over which an indicator changes color

Examples: phenolphthalein, methyl red, bromthymol blue….

Sherbet Activity

Make an acid/base reaction in your mouth to create the flavor of sherbet.

In a small paper cup combine the following ingredients: 1/2 teaspoon of citric acid crystals 1 teaspoon of icing sugar 1/2 teaspoon of drink crystals 1/4 teaspoon of sodium bicarbonate (baking soda = base)

Mix the ingredients with a popsicle stick. Enjoy the sherbet (but not all at once). It foams in

your mouth!

Wrap Up

Go Fish Time!

Today…Turn in:

NothingOur Plan:

Slap Jack NamesIndicator LabWrap Up – Spoons & Slap Jack

Homework (Write in Planner):Indicator Lab Today

LAB TIME!

Test every item with all of the indicators to determine the pH by placing 10 drops of the item to be tested in each test tube and adding 2 drops of the indicator. Then use the provided charts to determine the pH. The group that gets closest to the actual pHs will get 10 EXTRA CREDIT POINTS! If a member of your group has an electronic device out you are disqualified!

The Correct Answers

Item Actual pH7-UP 3.40

Vinegar 1.20

Fruit Juice 3.86

Lime Water 2.45

Tap Water 6.90

Soapy Water 3.61

Ammonia 12.01

Sour Candy 3.07

Crushed Aspirin 3.00

Today… Get Out:

Notes, WS Packet, Calculator Indicator Lab Make Up in ELO Today

Our Plan: Demo – Rainbow in the Blue Notes – Neutralization/Titrations Worksheet #3 Gizmo Standardize a Base Lab

Homework (Write in Planner): WS #3 Due Next Class

Rainbow Indicator Demos

http://www.youtube.com/watch?v=VMk37PX_bFI

http://www.youtube.com/watch?v=PdprNTwb4Ks

Polyprotic Acids

Acids such as H2SO4 , H3PO4 or H2CO3 that have more than one hydrogen (proton) to donate.

Polyprotic Acids

1 mole of H3PO4

Ionized…3 moles H+1 1 mole PO4

-3=

Neutralization

Occurs when equal molar amounts of acid and base are added.

In neutralization:Acid + Base --> Salt + Water

Neutralization Reaction

Example: HCl + NaOH NaCl + H2O

Neutralization

The number of moles of each substance needed depends on the ratio of H+1 to OH-1.

If it’s 1:1, the same amount of each is needed.

If there are 2 hydrogens to every 1 hydroxide, you would need twice as much base

Examples

_____ moles NaOH with 6.0 moles HCl

_____ moles H2SO4 with 4.0 moles KOH

6.0

2.0

Examples

_____ moles H2SO4 with 6.0 moles Al(OH)3

_____ moles H3PO4 with 15.0 moles LiOH

9.0

5.0

Neutralization

Neutralization & Titrations

Definitions:Titration: The process in which a

standard solution is added to a solution of unknown concentration to determine its concentration.

End Point: The point in a titration when the indicator changes color.

Titrations What is needed for a titration?

1. A solution whose concentration is known = Standard Solution

2. An accurate way to measure the volume of that solution = Buret

3. A way to determine when the reaction is complete = Indicator

Titration

What is a titration?

Buret filled with standard solution

Flask filled with solution of unknown concentration

Titration Video

TitrationsAcid Base Titrations are

reactions between strong acids and strong bases.

H+1 + OH-1 H2O

By doing a titration, you can calculate how many moles of acid and base there are.

Titrations

If the amount of either H+1 or OH-1 are known, the amount of the other can be calculated. (1:1 Ratio)

Titrations

To Calculate: Remember Molarity?

M = moles

LConcentration of solution

Moles of solution

Volume of solution

Titrations

Remember Dilutions?

MAVA = MBVB

Concentration of Standard Acid Solution

Volume of Standard Solution

Concentration of Unknown Base Solution

Volume of Unknown Solution

Example

After titrating, you found that 50 mL of 0.1 M HCl was neutralized by 29 mL of NaOH. What was the Molarity of the base?

Example

MAVA = MBVB

Use Algebra to solve for x!x = 0.17 M

50 mL0.1 M X 29 mL

Example 2

After titrating, you found that 48 mL of 0.5 M NaOH was used to neutralize 25 mL of HCl. How many moles of HCl are in the flask, AND what is its concentration?

Example

MAVA = MBVB


25 mLx 0.5 M 48 mL

Example Continued

Now find the number of moles…

M = moles

L0.96 M

X

0.025 Lx = 0.024 moles

Try It Out!

After titrating, you found that 53 mL of 0.05 M NaOH was used to neutralize 36 mL of HCl. What was the concentration of the HCl?

Try It Out!

MAVA = MBVB


36 mLx 0.05 M 53 mL

CONGRATULATIONS!

YOU HAVE COMPLETED ALL OF THE CURRICULUM FOR GENERAL CHEMISTRY!

Homework Time!

Complete WS #3 by next class!

Gizmo

If you have never logged in to Gizmos before use the code:AE462EHSKZAE38GSQZ5VAE53MQIMSVAE5YGBAF8Z

Wrap Up

What 3 things do you need for a titration?

Today… Turn in:

WS#3 Our Plan:

Review Quiz WS#3 Work Day

Missing Assignments/Labs/Quizzes Test Review

Bluff Homework (Write in Planner):

Test Review Due Next Class TEST NEXT CLASS!

Review Problem

Complete the Worksheet #3 Review Problem on p. 19 of your notes.

Today… Turn in:

Test Review to Check Our Plan:

Station ReviewTest Review QuestionsTestWork Quietly/Start Final Study Guide

Homework (Write in Planner):Nothing

Today… Turn in:

Goal Sheet Our Plan:

Antacid Lab TestWork on Final Test ReviewWrap Up – Present your findings to the

class Homework (Write in Planner):

Nothing

Today…Turn in:

Antacid LabOur Plan:

Final Test Review (30 points)Prepare Your NotecardReview Board Game

Homework (Write in Planner):Test Review Due Next Class

Today…Turn in:

Final Test ReviewOur Plan:

Take the FinalPencil, Scratch Paper, PT, Notecard, Calculator

Relax/StudyHomework (Write in Planner):

Have a Great Summer! Come back and visit me! I’ll miss you!

Today… Before Class: Grab a Lab Packet, Safety Goggles, and Apron Our Plan: Inquiry Lab Wrap Up...

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