8.11: End of Chapter Problems

Neutralization Reaction

Write a double replacement reaction of

a. stomach acid with milk of magnesia

b. stomach acid with tums

c. vinegar and egg shell

d. hydrochloric acid and sodium hydroxide.

Acids and Bases

1. Give the formula of the following.

Phosphoric acid Carbonic acid Hydroiodic acid Hydrofluoric acid

potassium hydroxide Calcium bicarbonate Barium hydroxide Lithium carbonate

2. Give the name of the following:

HCl (aq) HBr (aq) HNO₃ (aq) H₂SO₄ (aq)

NaOH KHCO₃ Na₂CO₃ CaCO₃

Bronsted-Lowry Acids and Bases

1. What is the formula and name for the conjugate base of each of the following acids?

H₂CO₃ H₂SO₄ HCO₃^- H₂PO₄^-

HSO₄^- HPO₄^2- H₃PO₄ HNO₃

2. What is the formula and name for the conjugate acid of each of the following bases?

F^- NH₃ CN^- NO₂^-

OH^- CH₃NH₂ Cl^- PO₄^3-

3. Identify the Bronsted-Lowry acids and bases for the forward and reverse reaction of each.

F^-(aq) + HCl(aq) ⇌ HF(aq) + Cl^-(aq)

CH₃CO₂H(aq) + NO₃^-(aq) ⇌ CH₃CO₂^-(aq) + HNO₃(aq)

PO₄^3-(aq) + NH₄⁺(aq) ⇌ NH₃(aq) + HPO₄^2-(aq)

HCN(aq) + H₂PO₄^-(aq) ⇌ CN^-(aq) + H₃PO₄(aq)

NH₄⁺(aq) + SO₄^2-(aq) ⇌ NH₃(aq) + HSO₄^2-(aq)

CN^-(aq) + HI(aq) ⇌ HCN(aq) + I^-(aq)

OH^-(aq) + HNO₃(aq) ⇌ HOH(l) + NO₃^-(aq)

HPO₄^2-(aq) + CO₃^2-(aq) ⇌ PO₄^3-(aq) + HCO₃^-(aq)

Equilibrium

1. True or False

a. The concentration of the reactants is always equal to the concentration of the products.

b. The reactants are not converted to products.

c. The rate of the forward reaction is equal to the rate of the reverse reaction.

d. The forward and reverse reactions stop.

e. The concentration of the reactants and products does not change.

f. The rate of the forward reaction is greater than the rate of the reverse reaction.

2. Balance the following chemical equations and write the equilibrium constant expression.

CH₄(g) + H₂O(g) ⇌ H₂(g) + CO(g)

H₂(g) + N₂(g) ⇌ N₂H₄(g)

SO₂(g) + O₂(g) ⇌ SO₃(g)

CS₂(g) + H₂(g) ⇌ CH₄(g) + H₂S(g)

PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)

3. Balance the following chemical equations and write the equilibrium constant expression.

C(s) + CO₂(g) ⇌ CO(g)

NH₃(aq) + H₂O(l) ⇌ NH₄⁺(aq) + OH^-(aq)

H₂SO₄(aq) + H₂O(l) ⇌ H₃O⁺(aq) + SO₄^2-(aq)

4. For each reaction, which is greater at equilibrium, the concentration of reactants or products?

Hint: Write an equilibrium constant expression and determine based on the value of the K_eq provided.

HPO₄^2-(aq) + CN^-(aq) ⇌ PO₄^3-(aq) + HCN(aq) K_eq = 8.6 X 10^-4

H₃PO₄(aq) + CN^-(aq) ⇌ H₂PO₄^-(aq) + HCN(aq) K_eq = 1.5 X 10⁷

HCO₃^-(aq) + HF(aq) ⇌ F^-(aq) + H₂CO₃(aq) K_eq = 1.5 X 10³

_NH4⁺(aq) + HCO₃^-(aq) ⇌ H₂CO₃(aq) + NH₃(aq) K_eq = 1.5 X 10^-3

Strong and Weak Acids

1. Based on the Ka value provided., indicate which acid is stronger of the pair? Which has a lower pH?

a. HClO, K_a = 3.0 X 10^-8

b. C₂O₄H^-, K_a = 6.4 X 10^-5

2. Based on the Ka value provided., indicate which acid is stronger of the pair? Which has a lower pH?

a. C₂O₄H₂, K_a = 5.9 X 10^-2

b. C₆O₂H₈, K_a = 1.7 X 10^-5

3. Based on the Ka value provided., indicate which acid is stronger of the pair? Which has a lower pH?

a. NH₄⁺, K_a = 5.6 X 10^-10

b. HPO₄^2-, K_a = 4.2 X 10^-13

The pH Scale

Find the pH, given the [H₃O⁺] of the following. Label the solution as acidic, basic, or neutral.

a. 1 ×10^-3 M b. 2.5 ×10^-11 M

c. 4.7 ×10^-9 M d. 5.8 ×10^-4 M

e. 1.0×10^-7 M f. 3.9 ×10^-2

g. 7.0 ×10^-5 h. 6.8 ×10^-7

Le Chatelier's principle

1. For the equilibrium below, what is the effect (give shift) of

S₂(g) + C(s) ⇌ CS₂(g)

a. increasing [CS₂]

b. decreasing [CS₂]

c. decreasing [S₂]

2. The enzyme carbonic anhydrase catalyzes the conversion of CO₂ and H₂O into H₂CO₃.

CO₂(g) + H₂O(l) ⇌ H₂CO₃(aq)

Give shift for b thru f.

a. Write the equilibrium constant expression.

b. What is the effect of doubling the amount of carbonic anhydrase on the equilibrium?

c. What is the effect of increasing [CO₂]?

d. What is the effect of decreasing [CO₂]?

e. What is the effect of increasing [H₂CO₃]?

f. What is the effect of decreasing [H₂CO₃]?

3. The following reaction happens in step 1 of the citric acid cycle:

Oxaloacetate + Acetyl-CoA + H₂O ⇌ Citrate + CoA

Give shift for a thru c.

a. What is the effect of decreasing [oxaloacetate]?

b. What is the effect of increasing [oxaloacetate]?

c. What is the effect of increasing [Acetyl-CoA]?

4. The following reaction is from step 5 of glycolysis:

Dihydroxyacetone phosphate ⇌ Glyceraldehyde-3-phosphate

a. What is the effect of removing [Glyceraldehyde-3-phosphate]?

b. What is the effect of adding [Dihydroxyacetone phosphate]?

Buffers

1. What is a buffer solution? What is the composition of a buffer solution? Give an example.

2. Explain with chemical equations, how the H₂CO₃/HCO₃^- buffer system helps maintain blood serum at a constant pH.

3. What is the effect of changes in pH on an enzyme structure? Please use the picture of a partial protein strand to show the effect using chemical equations.

4. Severe cases of acidosis may lead to coma and death. Explain with equilibrium equations & Le Chatelier’s principle how the lungs compensate for acidosis.

5. A patient has symptoms of light-headedness associated with acidosis. Explain how the kidney’s compensate for acidosis. Give equilibrium equations and apply Le Chatelier’s principle to explain your answer.

6. Due to excessive use of antacids a patient shows symptoms of alkalosis. Explain how the lungs try to compensate for alkalosis. Give equilibrium equations and apply Le Chatelier’s principle to explain your answer.

7. Symptoms of alkalosis include nervousness and cramps. Explain with chemical equations & equilibrium principles how the kidneys help compensate for alkalosis.