Exam 4B, Spring 2018

1. Complete and balance the following in aqueous solution.

a. Ni(NO3)2(aq) + Cs2S(aq)

b. HNO3(aq) + Cu(OH)2(s)

c. ClO2–(aq) → ClO–(aq) + ClO4–(aq)

d. BrO3–(aq) + [Cr(OH)4]–(aq) → CrO42–(aq) + Br–(aq)

2. Consider the reaction between solid calcium hydroxide and aqueous H3PO4.

a. Write the balanced reaction.

b. Find ΔH° for the reaction at 25 °C.

c. Find ΔS° for the reaction at 25 °C.

d. Find ΔG° for the reaction at 25 °C.

e. Find ΔG° for the reaction at 50 °C.

f. Does the spontaneity for the reaction increase or decrease as the temperature is raised?

3. Give the oxidation numbers for each atom in (NH4)2[PbI4].

4. Consider the cell: Ag(s) | Ag+(aq) || O2(g), pH = 0 | Pt(s)

a. Write the oxidation half-reaction.

b. Write the reduction half-reaction.

c. Write the net reaction.

d. Find the cell potential at standard conditions and 25 °C.

e. Is this a voltaic cell or an electrolytic cell? Why?

f. Will the cell potential increase, decrease, or stay the same as the pH is increased? Why?

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