CHEM 1200
Practice Test 4

Note: These questions are representative of the types of questions you can expect on the test. The actual test will be longer, typically between 20-40 questions. You will need to bring a SCANTRON answer sheet to each test.


1. Calculate E^o_cell for the following reaction:

2Fe²⁺(aq) + Cd²⁺(aq) ® 2Fe³⁺(aq) + Cd(s)

a. - 0.37 V
b. + 0.37 V
c. - 1.17 V
d. + 1.17 V
e. none of the above


2. Pick out the one reaction below that will occur spontaneously

a. Mg²⁺ + Ca ® Mg + Ca²⁺
b. Au + 3K⁺ ® Au³⁺ + 3K
c. 2Al³⁺ + 3Fe ® 2Al + 3Fe²⁺
d. Cu + 2H⁺ ® Cu²⁺ + H₂

3. Given the following standard reduction potentials in acid solution

Al³⁺ + 3e^- ® Al (s)                        E^o = -1.66 V
AgBr (s) + e^- ® Ag (s) + Br^-         E^o = + 0.07 V
Sn⁴⁺ + 2e^- ® Sn²⁺                        E^o = + 0.14 V
Fe³⁺ + e^- ® Fe²⁺                          E^o = + 0.77 V

Which of the following is the strongest oxidizing agent?

a. Fe³⁺
b. Fe²⁺
c. Br^-
d. Al³⁺
e. Al


4. Which one of the following reagents is capable of transforming Cu²⁺(1 M) to Cu(s) ?

a. I^- (aq)
b. Ni (s)
c. Ag⁺ (1M)
d. Al³⁺ (1M)
e. H⁺ (1M)


5. Which of the following is the strongest oxidizing agent under standard conditions?

a. Ag⁺ (aq)
b. H₂ (g)
c. H⁺ (aq)
d. Cl₂ (g)
e. Al³⁺ (aq)


6. Which of the following species has the highest entropy (DS^o) at 25^oC?

a. H₂O (s)
b. CO (g)
c. NaCl (s)
d. H₂O (l)
e. Fe (s)


7. Which response includes all the following processes that are accompanied by an increase in entropy.

a. I₂(s) ® I₂(g)
b. 2I(g) ® I₂(g)
c. 2NH₃(g) ® N₂(g) + 3H₂(g)
d. Mg²⁺(aq) + 2OH^- (aq) ® Mg(OH)₂(s)


e. Both a and c 8. Calculate DS for the reaction

SO₂(s) + NO₂(g) ® SO₃(g) + NO(g)
Given the following absolute entropies.

                     DS^o(J/K·mol)
SO₂(g)             248.5
SO₃(g)              256.2
NO(g)               210.6
NO₂(g)             240.5

a. 53.6 J/K
b. - 53.6 J/K
c. -22.2 J/K
d. 474.8 J/K
e. - 474.8 J/K


9. In which process is the system entropy increasing?

I. Expansion of a gas into a vacuum.
II. Vaporization of a liquid.
III. Precipitation of a solid from solution

a. All of them
b. only II and III
c. only I and III
d. only I and II
e. only III



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