Question

1. In thermochemistry, a "coupled reaction" is based on the conceptthat:

A. all reactions reach a thermodynamic equilibrium ("coupling") ata specific set of conditions
B. the enthalpy and entropy of a reaction are interdependent("coupled") on each other
C. a thermodynamically favorable reaction can be used to drive athermodynamically unfavorable reaction by "coupling" the tworeactions together simultaneously

D. a nonstandard-state reaction can be "coupled" with astandard-state reaction to result in a spontaneous process(negative ?G)

E. "like dissolves like" and "opposites attract"
^^NOT D

2. Calculate the E°cell for the following voltaic cell (use thestandard electrode potentials given on page 829 of the textbook, orfrom some other source):

Ni(s) + 2 Ag+(aq) ? Ni2+(aq) + 2Ag(s)

A. +1.85 V
B. –0.55 V
C. +1.05 V
D. –1.05 V
E. +0.55 V
^^NOT A
3. The exothermic reaction NH3(g) + HCl(g) ? NH4Cl(s) proceedsspontaneously at 25°C even though there is a decrease in disorderin the system (gases producing a solid). Why?

A. the exothermic reaction increases the temperature from 25°C to ahigher temperature which increases the T?S component


B. there is a phase change from gases to solid which means ?G iszero which, when combined with a negative ?H, results in aspontaneous process


C. the decrease in entropy of the system is offset by an increasein the entropy of the surroundings caused by the absorption of heatby the system from the surroundings


D. the decrease in entropy of the system is offset by an increasein the entropy of the surroundings caused by the release of heatfrom the system to the surroundings
^^ NOT B

4. Which of the following is the oxidation half-reaction of thisoxidation-reduction reaction?

Mg(s) + 2Ag+(aq) ? Mg2+(aq) + 2Ag(s)

A. Mg(s) ? Mg2+(aq) + 2e-
B. Mg2+(aq) + 2e- ? Mg(s)
C. 2Ag+(aq) + 2e- ? 2Ag(s)
D. 2Ag(s) ? 2Ag+(aq) + 2e-
^NOT C