AP Chemistry Unit 9 Progress Check: MCQ
1. Based on the information given, which of the following is a major difference between the zinc-
mercury cell and the lithium-iodine cell?: B. During the initial cell operation, each reaction is
thermodynamically favorable, but the larger operating potential of the lithium-iodine cell indicates that
its cell reaction is more thermody- namically favorable.
2. On average, after one year of operation, the potential of a lithium-iodine cell decreases by 1%-
2%. Which of the following best helps to explain the cause for the decrease in cell potential?: D.
Ecell=E°cell RT/nF lnQ, and as the cell operates, Q increases.
3. The use of zinc-mercury cells in hearing aids has been replaced by zinc-air cells that operate
using the oxidation of Zn by O2 from the air, generating a potential of +1.60V. Table 2 provides
the standard reduction potentials for the half-reactions used in zinc-mercury and zinc-air cells.
Which of the following best explains the modification to the cell design that is mostly responsible
for the difference in standard cell potentials for zinc-mercury and zinc-air cells?: A. The greater
standard cell potential of the Zn-air cell compared to that of the zinc-mercury cell most likely results
from the thermodynamically more favorable reduction of O2 compared to HgO.
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, AP Chemistry Unit 9 Progress Check: MCQ
4. The diagrams above represent physical changes for potassium. Which of the following
correctly identifies the physical process and provides the correct ”S ° for the process in the
indicated diagram?: A. In diagram 1, the process is freezing and ”S°freezing is negative.
5. Two samples containing an equal number of moles of N2(g) are kept in- side separate 1-liter
rigid containers. The particle diagrams above show the distribution of molecular speeds in each
sample. Based on the information given, which of the following identifies the sample with the
greater S°, and why?: B. Sample 1, because the N2 molecules have a larger distribution of energies
compared to sample 2.
6. A sample of an ideal gas at Pi is initially confined to one chamber of the ap- paratus
represented above, and the other chamber is initially evacuated. The valve connecting the
chambers is opened, and the gas expands at constant temperature to fill both chambers. Which of
the following best describes ”S for the process?: D. ”S>0 because the gas particles become
dispersed in a larger volume
7. The chemical equation above represents the formation of SeF6(g) from its elements and the tab
provides the approximate values of S° for Se(s) and SeF6(g). Based on the data, which of the
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1. Based on the information given, which of the following is a major difference between the zinc-
mercury cell and the lithium-iodine cell?: B. During the initial cell operation, each reaction is
thermodynamically favorable, but the larger operating potential of the lithium-iodine cell indicates that
its cell reaction is more thermody- namically favorable.
2. On average, after one year of operation, the potential of a lithium-iodine cell decreases by 1%-
2%. Which of the following best helps to explain the cause for the decrease in cell potential?: D.
Ecell=E°cell RT/nF lnQ, and as the cell operates, Q increases.
3. The use of zinc-mercury cells in hearing aids has been replaced by zinc-air cells that operate
using the oxidation of Zn by O2 from the air, generating a potential of +1.60V. Table 2 provides
the standard reduction potentials for the half-reactions used in zinc-mercury and zinc-air cells.
Which of the following best explains the modification to the cell design that is mostly responsible
for the difference in standard cell potentials for zinc-mercury and zinc-air cells?: A. The greater
standard cell potential of the Zn-air cell compared to that of the zinc-mercury cell most likely results
from the thermodynamically more favorable reduction of O2 compared to HgO.
1/
11
, AP Chemistry Unit 9 Progress Check: MCQ
4. The diagrams above represent physical changes for potassium. Which of the following
correctly identifies the physical process and provides the correct ”S ° for the process in the
indicated diagram?: A. In diagram 1, the process is freezing and ”S°freezing is negative.
5. Two samples containing an equal number of moles of N2(g) are kept in- side separate 1-liter
rigid containers. The particle diagrams above show the distribution of molecular speeds in each
sample. Based on the information given, which of the following identifies the sample with the
greater S°, and why?: B. Sample 1, because the N2 molecules have a larger distribution of energies
compared to sample 2.
6. A sample of an ideal gas at Pi is initially confined to one chamber of the ap- paratus
represented above, and the other chamber is initially evacuated. The valve connecting the
chambers is opened, and the gas expands at constant temperature to fill both chambers. Which of
the following best describes ”S for the process?: D. ”S>0 because the gas particles become
dispersed in a larger volume
7. The chemical equation above represents the formation of SeF6(g) from its elements and the tab
provides the approximate values of S° for Se(s) and SeF6(g). Based on the data, which of the
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