Exam 4B, Spring 2004

1. Complete and balance the following reactions:

a. Sr(OH)₂(s) + C₆H₅COOH(aq)

b. Co(NO₃)₃(aq) + Na₂CO₃(aq)

c. Ni²⁺(aq) + NH₃(aq)

d. MnO₄^–(aq) + HClO₃(aq) → Mn²⁺(aq) + HClO₄(aq)

e. MnO₄^–(aq) + Mg(s) → MnO₂(s) + Mg(OH)₂(s)

2. Identify the oxidation number for:

a. As in H₃AsO₄

b. Fe in Fe₂O₃

3. Cu(OH)₂ is a sparingly soluble salt. Determine if the solubility will increase, decrease, or stay the same in the following solutions. Briefly (15 words or less) explain your answer.

a. 1 M HCl solution.

b. 1 M Cu(NO₃)₂ solution.

c. 1 M NH₃ solution.

4. Consider the reaction of solid barium chloride with aqueous potassium hydroxide solution.

a. Write the reaction.

b. Find ΔH° at 25 °C.

c. Find ΔS° at 25 °C.

d. Find ΔG° at 25 °C.

5. Consider the cell:

Pt(s) | Co(OH)₃(s) | Co(OH)₂(s) | pH = 14 || ClO₃^–(aq) | Cl ^–(aq) | pH = 14 | Pt(s)

a. Write the oxidation half–reaction.

b. Write the reduction half–reaction.

c. Write the net reaction.

d. Find the cell potential under standard conditions.

Answers