AP CHEMISTRY UNIT 9 PROGRESS CHECK QUESTIONS AND ANSWERS 2025
Based on the information given, which of the following is a major difference between the zinc-mercury
cell and the lithium-iodine cell? - (ANSWER)B
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? - (ANSWER)D
The use of zinc-mercury cells in hearing aids has been replaced by zinc-air cells that operate using the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? - (ANSWER)A
The diagrams above represent physical changes for potassium. Which of the following correctly
identifies the physical process and provides the correct ΔS° for the process in the indicated diagram? -
(ANSWER)A
Two samples containing an equal number of moles of N2(g) are kept inside 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? - (ANSWER)B
A sample of an ideal gas at Pi is initially confined to one chamber of the apparatus 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 ΔS for the
process? - (ANSWER)D
The chemical equation above represents the formation of SeF6(g) from its elements and the table
provides the approximate values of S° for Se(s) and SeF6(g). Based on the data, which of the following
mathematical expressions can be used to correctly calculate S° for F2(g) ? - (ANSWER)D
The table above provides approximate S° values for several substances. Based on the information, which
of the following reactions has the largest increase in entropy, ΔS° ? - (ANSWER)A
, AP CHEMISTRY UNIT 9 PROGRESS CHECK QUESTIONS AND ANSWERS 2025
The chemical equation above represents the combustion of glucose, and the table provides the
approximate standard absolute entropies, S°, for some substances. Based on the information given,
which of these equations can be used to calculate an approximation of S° for H2O(g) ? - (ANSWER)B
An ice cube at 0°C melts when placed inside a room at 22°C (295K). Based on the concepts of enthalpy,
entropy, and Gibbs free energy, which of the following best explains why the process is
thermodynamically favorable? - (ANSWER)D
A 5.00g-sample of KOH(s) at 25.0°C was added to 100.0g of H2O(l) at room temperature inside an
insulated cup calorimeter, and the contents were stirred. After all the KOH(s) dissolved, the temperature
of the solution had increased. Based on the information given, which of the following best justifies the
claim that the dissolution of KOH(s) is a thermodynamically favorable process? - (ANSWER)B
Based on the information, which of the following statements best helps to explain whether or not the
reaction is thermodynamically favored at 298K? - (ANSWER)C
In an experiment done at a low temperature, one hour after the reaction started, Y was produced but
almost no Z was produced. At a much higher temperature, one hour after the reaction started, both Y
and Z had been produced. Which of the following best explains why very little Z was produced at the
lower temperature? - (ANSWER)A
Graphite, an allotrope of carbon, is converted into cubic diamond through a process that may take a
billion years or longer. As illustrated above, scientists can make synthetic diamonds using a certain
process in about one week. However, these synthetic diamonds have carbon atoms in a hexagonal
lattice. Diamonds with a carbon atoms in a cubic lattice are not produced even though they are
thermodynamically more stable than hexagonal diamond. Which of the following best justifies why the
synthetic process produces hexagonal diamond and not the more thermodynamically stable cubic
diamond? - (ANSWER)D
The hydrolysis of adenosine triphosphate (ATP) is represented by the equation above. This reaction is
critically important in cellular biology, but the reaction itself proceeds at a very slow rate. Based on the
information given, which of the following best explains why an enzyme (biological catalyst) is required
for the reaction to occur at a faster rate? - (ANSWER)D
Based on the information given, which of the following is a major difference between the zinc-mercury
cell and the lithium-iodine cell? - (ANSWER)B
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? - (ANSWER)D
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? - (ANSWER)A
The diagrams above represent physical changes for potassium. Which of the following correctly
identifies the physical process and provides the correct ΔS° for the process in the indicated diagram? -
(ANSWER)A
Two samples containing an equal number of moles of N2(g) are kept inside 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? - (ANSWER)B
A sample of an ideal gas at Pi is initially confined to one chamber of the apparatus 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 ΔS for the
process? - (ANSWER)D
The chemical equation above represents the formation of SeF6(g) from its elements and the table
provides the approximate values of S° for Se(s) and SeF6(g). Based on the data, which of the following
mathematical expressions can be used to correctly calculate S° for F2(g) ? - (ANSWER)D
The table above provides approximate S° values for several substances. Based on the information, which
of the following reactions has the largest increase in entropy, ΔS° ? - (ANSWER)A
, AP CHEMISTRY UNIT 9 PROGRESS CHECK QUESTIONS AND ANSWERS 2025
The chemical equation above represents the combustion of glucose, and the table provides the
approximate standard absolute entropies, S°, for some substances. Based on the information given,
which of these equations can be used to calculate an approximation of S° for H2O(g) ? - (ANSWER)B
An ice cube at 0°C melts when placed inside a room at 22°C (295K). Based on the concepts of enthalpy,
entropy, and Gibbs free energy, which of the following best explains why the process is
thermodynamically favorable? - (ANSWER)D
A 5.00g-sample of KOH(s) at 25.0°C was added to 100.0g of H2O(l) at room temperature inside an
insulated cup calorimeter, and the contents were stirred. After all the KOH(s) dissolved, the temperature
of the solution had increased. Based on the information given, which of the following best justifies the
claim that the dissolution of KOH(s) is a thermodynamically favorable process? - (ANSWER)B
Based on the information, which of the following statements best helps to explain whether or not the
reaction is thermodynamically favored at 298K? - (ANSWER)C
In an experiment done at a low temperature, one hour after the reaction started, Y was produced but
almost no Z was produced. At a much higher temperature, one hour after the reaction started, both Y
and Z had been produced. Which of the following best explains why very little Z was produced at the
lower temperature? - (ANSWER)A
Graphite, an allotrope of carbon, is converted into cubic diamond through a process that may take a
billion years or longer. As illustrated above, scientists can make synthetic diamonds using a certain
process in about one week. However, these synthetic diamonds have carbon atoms in a hexagonal
lattice. Diamonds with a carbon atoms in a cubic lattice are not produced even though they are
thermodynamically more stable than hexagonal diamond. Which of the following best justifies why the
synthetic process produces hexagonal diamond and not the more thermodynamically stable cubic
diamond? - (ANSWER)D
The hydrolysis of adenosine triphosphate (ATP) is represented by the equation above. This reaction is
critically important in cellular biology, but the reaction itself proceeds at a very slow rate. Based on the
information given, which of the following best explains why an enzyme (biological catalyst) is required
for the reaction to occur at a faster rate? - (ANSWER)D
