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Unit 13

Acids and Bases

Name: ___________________________ Period: ______ TEST: Wednesday 4/27/16

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Unit 13 – Acids and Bases – Calendar

Monday Tuesday Wednesday Thursday Friday

APRIL 7th

Solutions

Test

8th

Video: Acids & Bases

Notes #1

Acids and Bases

Characteristics and

Arrhenius and Bronsted

Lowry definitions

HW: Pg. 6

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Notes: pH scale:

HW: Pg. 9

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Go over Gas Law,

Bonding, and

Solutions Tests

HW: Study for

Cumulative Exam

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Cumulative

TEST

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pH and pOH

calculations -

Math Practice

HW: Pg 12

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Quiz?!?!?!

Crossword puzzle

Pg 13-14

Half day

End of 5th six weeks

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PHET Computer Lab

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Neutralization and

Titration Notes

HW: Pg 17

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Titrations – Pre Lab

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Titrations

HW: Study Guide

Pg 18-21

22 Titrations

HW: Study Guide

Pg 18-21

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Alien Juice Bar

Computer Lab

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STUDY GUIDE

DUE!

Review

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Acids &

Bases

TEST

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Notes #1: Introduction to Acids and Bases

Acid: ____________________________________________________________________________

Properties of Acids:

o ______________________________ (lemon juice)

o ___________________

o Both strong and weak

o Will cause indicators to change colors

o A metal + an acid will produce ___________________

o

o

o

o Single replacement reaction

Acid + Metal → ____________________ + a “__________”

o Double replacement reaction

Acid + Base → ___________ + a “__________”

Examples: HCl, soda, coffee

Naming Rules:

ION TYPE ION ENDING ACID NAME BEGINNING ACID ENDING

Polyatomic

-ite NO hydro- beginning -ous

-ate NO hydro- beginning -ic

Monatomic -ide hydro- beginning -ic

EX: Examples of Naming Binary Acids

• HCl

• HF

• HBr

EX: Examples of Naming Ternary Acids

• H2SO4 Sulfate is the poly, so __________________________________

• H2CO3 Carbonate is the poly, so ________________________________________________

• H2NO2 Nitrite is the poly, so __________________________________

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Base: _____________________________________________________________________________

Properties of Bases:

o ___________________

o ___________________ (soap)

o ___________________

o Both strong and weak

o Will cause an indicator to ___________________ colors

o

o

Examples: NaOH, soap, antacids, drano, bleach

Naming Bases

• The easiest are the bases, since most of these are ______________ hydroxides,

compounds you already know how to name.

• Metal hydroxides are named in the same way any other ionic compound is

named. First give the name of the __________________ ion. Follow this with

the name of the anion, which, in the case of bases, is “____________________”.

• KOH –

• Mg(OH)2 -

Other definitions of Acids and Bases

Arrhenius Acids and Bases:

o Acid: _______________________________________________________________________________.

o Base: _______________________________________________________________________________.

Brønsted – Lowry Acids and Bases

o They felt the Arrhenius definition was too limiting.

o Acids: __________________________________________________________________________

Brønsted – Lowry Acids and Bases cont.

o Bases: _________________________________________________________________________

Ex: NH3 + H2O ↔ NH4+ + OH-

EX: HCl + H2O ↔ H3O + + Cl-

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Amphoteric: __________________________________________________________________

Strong Acids/Bases: ____________________________________________________________

o Ex: HCl, NaOH

Weak Acids/Bases: ____________________________________________________________

o Ex: NH3, Acetic Acid (vinegar)

o Tooth decay is caused by the weak acid – lactic acid: C3H6O3

Strong Electrolytes

breaks apart into its ions

Are conductors of

electricity

Will produce a ___ light bulb

Examples of Acids and Bases that are Strong Electrolytes:

Weak Electrolytes

breaks apart into its ions

Are conductors of

electricity

Will produce a _______ light bulb

Examples of Acids and Bases that are Weak Electrolytes:

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HOMEWORK – DAY 1 NOTES

Which picture at right is the:

1. Strong electrolyte ______

2. Weak electrolyte ______

A B

IDENTIFICATION - Identify the following examples as: A = acid B = base S = salt (neither acid not base) Remember from the previous units, a salt is any ionic compound, excluding what we classify as a base. ____1. AgOH ____2. MgSO4

____3. ZnCO3

____4. H2SO4

____5. NaOH ____6. HClO

____7. Mg(OH)2

____8. HNO3

____9. Pb(ClO)2

____10. (NH4)2CO3

____11. HC2H3O2

____12. HBr

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pH SCALE Notes: pH and pOH

MEASURING pH Scientists use a pH scale to measure the strength of an acid or base. The term pH stands for “potential for hydrogen”. The amount of hydrogen in a substance determines its acidity or alkalinity. Alkaline is another term for base. A number on the pH scale is used to describe the strength of acidity or alkalinity. The most commonly used pH scale goes from 1 (very acidic) to 14 ( very basic). The number 7 on a pH scale means neutral – neither acid nor base. The concentration of hydrogen ions in a solution is described by its number on the pH scale.

• A _____________pH tells you that the concentration of ____________________________ ion

is _____________. EX: pH 2

• By comparison, a ___________________ pH tells you that the concentration of

_________________________ ion is ___________________. EX: pH12

Self-ionization of water: _____________________________________________________________________________________

________________________________________________________________________________________________.

H2O + H2O OH- + H3O+

Also written as: H2O H+ + OH-

The H3O+ and H+ represent hydrogen ions in solution.

Neutral Solutions

In pure water, the concentration of hydrogen ions is ______________________to the concentration of

hydroxide ions

1 x 10-7 M or pH of ______ o (Remember that M is the unit for Molarity)

[H+] = [OH-] o (brackets represent concentration)

The represents a ________________ _________________________

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Solutions

In a solution, if the [H+] _______________________ the [OH-] _____________________ and vice

versa. o Think back to our see-saw. As one “person” goes up the other “person” goes down.

Ion-product constant of water, Kw:

Kw = [H+] x [OH-] = 1 x 10-14 M

Acidic Solution:

The [H+] is ____________________________than [OH-].

Therefore, the [H+] is ____________________________________________________

Basic Solution:

The is [H+] less than [OH-].

Therefore, the [H+] is ______________________________________________

A.k.a. ___________________________________________________________

Let’s review: Complete the chart below:

Type of Solution pH Ranges [H+] versus [OH-] Example

Acidic Neutral Basic or Alkaline

Acids Bases

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Homework:

1. Use the pH scale on page 7 to rank battery acid, vinegar, orange juice, milk, and bleach in

order of increasing acidity.

2. Complete each section:

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pH CALCULATIONS

pH = - log[H+]

pH [H+]

Kw = [H+] [OH-]

Remember: The pH scale ranges from 0-14

o 0 = ______________________

o 7 = ______________________

o 14 = ______________________

pH = ___________________________

What is the pH of a neutral solution?

o Calculate using the Logarithmic function on the calculator

( see photo to the right)

Sample Problems

As long as you have a ____ x 10 to some power, the pH is the exponent. If the number before the

“x10” is anything other than 1, you MUST use the formulas to find the pH.

1. What is the pH of the following concentrations?

a. [H+] = 1 x 10-2M =

b. [H+] = 1 x 10-9 M =

c. [H+] = 1 x 10-5 M =

2. What is the pH of the following concentrations? Use pH = - log[H+]

a. [H+] = 2 x 10-2M =

b. [H+] = 6 x 10-9 M =

c. [H+] = 3 x 10-5 M =

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Other Formulas and Problems

pH 14 = pH + pOH (See example 1 below)

Using the Equilibrium constant labeled as _______________

Kw is ________________________

Kw = __________________________

EX: What is the pH of a solution with a [OH-] of 4.0 x 10-11M?

Use Kw to find [H+] then find pH using –log function.

Example Problems

1. If pH = 5, pOH =

Is this solution acidic, basic or neutral?

2. What is the pH of a solution that has a hydrogen ion concentration of 1.0 x 10-5M?

Is this solution acidic, basic or neutral?

3. What is the hydrogen ion concentration of a solution with a pH of 11? Which has a greater concentration:

H+ or OH-?

4. A solution has a hydrogen ion concentration of 1.2x10-8M. Determine the pH of the solution. Is this solution

acidic, basic or neutral?

5. Assuming Kw = 1x10-14, calculate the molarity of OH- in solutions at 25ºC when the H+ concentration is

0.2M.

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Homework Practice Problems on pH

Solve the following problems. Be sure to show work for each problem.

1. Determine the pH of a solution that has a hydrogen ion concentration of 1.0x10-9M.

Is this solution acidic, basic, or neutral?

2. Lime juice has a hydrogen ion concentration of 1.3x10-2M, while the [H+] in lemon juice in 0.067M.

Calculate the pH for each juice.

pH of lemon =

pH of lime =

Which is more acidic?

3. What is the hydrogen ion concentration for a solution with a pH of 8?

What is the pOH of the solution?

4. Knowing Kw = 1x10-14, calculate the molarity of OH- in solutions at 25ºC when the H+

concentration is:

a. 5 x 10-10 M

b. 100 M

5. Determine the pH of a solution if the [OH−

] = 4.93 × 10−8 . (Hint: solve for [H+] using Kw, then pH)

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REVIEW OF ACID/BASE PROPERTIES AND ELECTROLYTES

WORD BANK

corrosive strong dim slippery below

bright neutral all above I Chemistry

acidic weak hydroxide hydronium metals

amphoteric acid(s) base(s) red blue

hydrogen bitter sour electrolyte basic

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Hints for the Crossword Puzzle

Across

4. able to act as an acid or base.

6. Bases have a taste.

9. solutions contain hydrogen and hydroxide ions.

10. Acids will react with to produce hydrogen gas.

14. Acids have a taste.

17. An acid or a base can be called a(n) because either can

conduct an electric current.

18. For a weak electrolyte, the light bulb will be .

19. the name of the ion commonly found in bases

20. A electrolyte will partially dissociate.

Down

1. A electrolyte will completely dissociate.

2. harmful, destructive, caustic

3. the type of solution that has a higher hydrogen ion concentration the hydroxide

ion concentration

4. Fruits and vinegar are examples of .

5. Bleach, ammonia, and soap are all examples of .

7. Bases feel .

8. For a strong electrolyte, the light bulb will be .

11. For bases, the pH is seven.

12. Bases turn litmus paper .

13. For acids, the pH is seven.

15. the color of pH paper in an acidic solution

16. the element commonly found in acids

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Neutralization Notes

Acid-Base reactions will produce _______________ ____________________ when completely

neutralized.

Salts are compounds consisting of a(n) ____________________ from an acid and a(n)

_______________ from a base.

In general, reactions in which an acid and a base react in an aqueous solution to produce a salt and

water is called Neutralization Reactions.

Neutralization occurs when an Acid + Base ↔ ______________ + __________

o Salt: Anion from acid and the cation from the base join together to form a salt.

Where do we see this process?

o _____________

o Farmers controlling the ___________ of soil

o Formation of ______________

A strong acid + a strong base = neutral solution

o Examples:

HCl + NaOH ↔ H2O + NaCl

HCl + KOH ↔ H2O + KCl

Practice: Don’t forget to balance them after you write them.

HCl + LiOH →

HNO3 + CsOH →

HBr + KOH →

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Titrations Titration:______________________________________________________________________________

______________________________________________________________________

o If you don’t know the concentration of one solution, you can figure it out by performing a

neutralization reaction, or titration, with a __________________ ______________________.

o A standard solution is one of ________________ ________________.

Performing Titrations

o Steps in a neutralization reaction:

A measured volume of an _______________ solution of ________________

concentration is added to a flask.

Several drops of ________ are added to the solution.

Measured volumes of a ________ with a ________ concentration are mixed into the acid

until it barely changes color.

o End Point: __________________________________________________________

Once you have reached the end point, you can perform calculations to find the unknown

solution.

3. Example: A 25 mL solution of H2SO4 is completely neutralized by 18 mL of 1.0 M NaOH. What is the

concentration of H2SO4 solution?

a. Step 1: Balance Equation

____H2SO4 + ____NaOH ____Na2SO4 + ____H2O

b. Step 2: Use this formula to solve for unknown concentration.

________________ = _________________

na = number of ____________ of your ____________ (Coefficient)

nb = number of ___________ of your _____________ (Coefficient)

M = _________________

V = __________________

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Neutralization Reactions can also be asked like this:

1. How many moles of HCl are needed to neutralize 6 mols of KOH?

a. 1st ask, what is the mol ratio and then set it up as a proportion.

2. H2SO4 + 2NaOH ↔ Na2SO4 + 2H2O

a. One mole of sulfuric acid is needed to neutralize moles of NaOH.

b. How many moles of NaOH are needed to neutralize 4 moles of H2SO4?

Neutralization and Titration Homework

1. What is the purpose of a titration?

2. Why do you need an indicator in a titration?

3. What is the endpoint?

4. Why is it important not to “overshoot” the titration? Refer to your answer to #1.

5. Calculate the molarity of an acetic acid solution if 34.57 mL of this solution are needed to neutralize 25.19 mL

of 0.1025 M of sodium hydroxide. Balance the equation as needed!!!!

____HC2H3O2 (aq) + ____ NaOH (aq) ____ Na C2H3O2 (aq) + _____ H2O (l)

6. 50 mL of 0.60 M sodium hydroxide neutralized 20 mL of sulfuric acid. Determine the concentration of the acid.

BALANCE THE EQUATION FIRST! ___ H2SO4 (aq) + ___ NaOH <-> ___ Na2SO4 (aq) + ___ H2O (l)

7. 25.0 mL of 0.10 M nitric acid neutralized 40.0 mL of barium hydroxide. Determine the concentration of the base.

BALANCE! ___ HNO3 (aq) + ___ Ba(OH)2 (aq) <-> ___ Ba(NO3)2 (aq) + ___ H2O (l)

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Acid/Base STUDY GUIDE

This is due on 4/26/16 and must be completed in its entirety to earn +5 points on the test.

Acid and Base definitions:

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1. What are the properties of acids? 2. What are the properties of bases?

3. Label as Acid (A), Base(B) or Salt(S) a. HCl _______

b. H3PO4 _______

c. HNO2 _______

d. LiOH _______

e. H2SO3 _______

f. H3P _______

g. Mg(OH)2 _______

h. NaCl _______

i. KNO3 _______

4. What are the products of the self-ionization reaction of water?

5. What does Kw stand for?

6. What is the value of Kw

7. Write the equation for Kw:

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8. Finish the equations:

pH =

pOH=

pH + pOH=

9. What is the range for the pH scale?

10. What is the equation used for a titration?

11. Write a complete and balanced equation for the following acid-base reaction:

a. H3PO4 + Ca(OH)2

b. HCl + Mg(OH)2

12. Calculate the concentration of hydrochloric acid if 125.0mL of this acid is neutralized by 60.0mL of 2.0M sodium

hydroxide? ____ HCl (aq) + _____NaOH (aq) ____ H2O (l) + ____ NaCl (aq)

13. Calculate the concentration of sulfuric acid if 60.0mL of this acid is neutralized by 10.0mL of .10M potassium hydroxide? ___ H2SO4 (aq) + ___ KOH (aq) <-> ___ K2SO4 (aq) + ___ H2O (l)

14. What is the molarity of 3.50 L of solution that contains 90.0g of sodium chloride?

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15. How many moles of HCl are present in 0.8 L of a 0.5M HCl solution?

16. How many milliliters of 16.0 M HNO3 would be required to prepare 750 mL of a 0.5 M solution?

17. Complete the chart:

remember Kw = [H+][OH-] and pH = -log[H+] and pH + pOH = 14

Given Solve for Acidic, Basic, or Neutral?

(A/B/N)

pH = 7 pOH =

pOH = 12.5 pH =

[H+] = 2.6 x 10 -4 pH =

[H+] = 1.0 x 10 -8 pH =

[OH-] = 1.0 x 10-10 [H+] =

[OH-] = 5.2 x 10-3 [H+] =

[H+] = 1.0 x 10 -7 [OH-] =

[H+] = 9.1 x 10 -13 [OH-] =

Kw = 1.00 x 10 -14 (mol/L)2