Unit 12
Acids and Bases
Chemistry Assignments and Objectives
EQ: Why does treating icy roads make your car rust?
Lesson 1 – Learning Targets
1.
2.
3.
4.
5.
6.
7.
Identify the physical and chemical properties of acids and bases.
Classify solutions as acidic, basic or neutral.
Explain how to recognize an Arrhenius acid (H+) and an Arrhenius base (OH-).
Distinuguish between a Bronsted-Lowry acid and a Bronsted-Lowry base.
Identify the acid and the base in a Bronsted-Lowry conjugate acid-base pair.
Define substances (such as water) that can act as either an acid or a base as amphoteric.
Recognize monoprotic and polyprotic acids.
Lesson 1 – Homework Problems
1. Identify the conjugate acid-base pairs in the following reactions.
a) NH4 + (aq) + OH – (aq)  NH3 (aq) + H2O (l)
b) HBr (aq) + H2O (l)  H3O + (aq) + Br – (aq)
c) CO3 2- (aq) + H2O (l)  HCO3 – (aq) + OH – (aq)
d) HSO4 – (aq) + H2O (l)  H3O + (aq) + SO4
2-
(aq)
Lesson 2 – Learning Targets
1. Explain the meaning of pH and pOH.
2. Calculate pH and pOH of aqueous solutions.
3. Recognize that all aqueous solutions have both a pH and a pOH and that the two always sum up to 14.
Lesson 2 – Homework Problems
1. State whether each solution is acidic, basic or neutral.
a) [H + ] = 1.0 x 10 -13 M
b) [OH - ] = 1.0 x 10 -7 M
c) [OH - ] = 1.0 x 10 -3 M
2. Calculate the pH of the following.
a) [H + ] = 1.0 x 10 -2 M
b) [H + ] = 3.0 x 10 -6 M
3. Calculate the pH and pOH of the following.
c) [OH - ] = 8.2 x 10 -6 M
a) [OH -] = 1.0 x 10 -6 M
b) [OH - ] = 6.5 x 10 -4 M
c) [H + ] = 3.6 x 10 -9 M
d) [H + ] = 0.025 M
4. Calculate the [H + ] and [OH - ] of the following.
a) pH = 2.37
b) pH = 11.05
c) pH = 6.50
Lesson 3 – Learning Targets
1.
2.
3.
4.
5.
6.
Write chemical equations for neutralization reactions: Acid + Base = a Salt + water
Explain how neutralization reactions are used in acid-base titrations.
Distinguish between the equivalence point and the endpoint of a titration.
Explain how and why indicators are used.
Describe salt hydrolysis and determine whether a salt solution is acidic, neutral or basic.
Compare the properties of buffered and unbuffered solutions.
Lesson 3 – Homework Problems
1. What is the molarity of a CsOH solution if 30.0 mL of the solution is neutralized by 26.4 mL of 0.250 M
HBr solution?
2. What is the molarity of a nitric acid solution if 43.33 mL 0.1000 M KOH solution is needed to neutralize
20.00 mL of the nitric acid?
3. Write the formulas for the acid and base which produce each of the following salts. Determine if each salt is
acidic, basic or neutral.
Salt
Sodium Acetate
Ammonium Nitrate
Lithium Phosphate
Potassium Nitrate
Sodium Sulfate
Acid
Base
A/B/N
Unit 12 Review
Acids and Bases Practice
Label the acids and bases in the following Bronsted-Lowry reactions. Connect the conjugate pairs with a
line.
1.
C2H3O2- + H2O  HC2H3O2 + OH-
2.
NH4+ + H2O  NH3 + H3O+
3.
C6H5NH2 + NH3  C6H5NH3 + NH2-
4.
H2COO- + H2O  H2COOH + OH-
5.
HF + CH3CH2NH2  F- + CH3CH2NH3+
Find the pH of each of the following solutions given their concentrations and tell whether the solution is
an acid or a base.
6.
[H+] = 1.0 x 10-1 M
9. [H+] = 1.0 x 10-8 M
10.
[OH-] = 5.48 x 10-9 M
11. [H+] = 4.35 x 10-12 M
12.
What is the molarity of a solution of HCl if you have 32.5 grams dissolved in 0.500 L?
13.
What is the pH of a solution that has a volume of 2.50 L and contains 5.33 grams of HCl?
Titration/Neutralization (don’t forget to balance the equations!)
1. A volume of 30.0 mL pf 0.25 M HCl neutralizes a 50.0 mL sample of KOH solution. What is the
concentration of KOH?
2. A volume of 9.0 mL of 0.70 M NH4OH neutralizes a 35 mL sample of HClO4 solution. What is the
concentration of HClO4?
3. How many mL of 0.36 M Ca(OH)2 neutralizes a 75-mL sample of 0.5 M HClO solution?
Solutions/dilutions
1. If you mixed 35 grams of dry NaOH with 150 mL of H2O what would the solution’s molarity be?
2. How many grams of HCl would be needed to make 2.0 L of a 1.00 M solution?
3. How much water should 15 mL of 15.0 M H2SO4 be added to so it is diluted to 1.0M?
4. If you have 215 mL of a 2.5 M solution of CuSO4 and added 115 mL of water to it, what would its new
concentration be?
Find the pH, pOH, [H+], [OH-] of each of the following:
1.
[H+] = 1.0 x 10-3 M
6. pH = 3.3
2. pH = 10.2
7. pOH = 4.6
3. pOH = 9.5
8. [OH-] = 1.2 x 10-3 M
4. pH of 2.3
9. [OH-] = 4.3 x 10-5 M?
5.
10. pH = 12.1
pH = 6.7
Units 11 and 12 Combined Review
1.
What are the properties of acids? What are the properties of bases?
2. Describe Arrhenius acids and bases. Give examples of each.
3. Describe Bronsted-Lowry acids and bases. Give examples of each.
4. Name the strong acids. Name the strong bases.
5. Describe a monoprotic acid. Give an example.
6. Describe a polyprotic acid. Give an example.
7. How many mL of a 12.1 M solution of HCl would be needed to make .75 L of 0.5 M HCl?
8. How many grams of CuSO4 would be needed to make 50 mL of a 0.1 M solution?
9. What are the Bronsted-Lowry acid and base, and conjugate acid and base in the following equilibrium
reaction? Explain why.
NO3- + H2O ↔ HNO3 + OH10. What is the pH, pOH, [H3O+], and the [OH-] of a solution that has a hydroxide ion concentration of 5.01
x 10-11 M ?
11. What is the pH, pOH, [H3O+], and the [OH-] of a solution that has a hydrogen ion concentration of 2.01
x 10-4 M ?
12. A student performs a titration experiment and finds that 78.6 mL of 0.5 M NaOH is required to
neutralize 60.0 mL of aqueous HNO3. Determine the molarity of the HNO3 solution.
NaOH + HNO3 → H2O + NaNO3
13. Explain what a salt is and how to determine its pH.
14. What is an electrolyte—be specific.
15. How many grams of KNO3 are in 350 mL of a saturated solution at 60°C ? (Use the solubility graph.)