Ap chemistry Unit 7 Progress Check: MCQ
Questions With High Ratings
Which of the following changes to the particle diagram will best represent the effect of adding 1.0mL of
4MNaCl to the solution? - Correct Answer B.
Some of the Cu+ and Cl− ions combine to form CuCl(s) because the molar solubility will be lower than
4×10−4M
Which of the following best explains what the particle diagram is able to show about the entropy change
for the dissolution of CuCl(s) in pure water? - Correct Answer A.
The particle diagram shows that the dissociation of CuCl(s) into ions contributes to an increase in the
entropy for the dissolution.
Which of the following best explains whether or not the particle diagram can predict the relative value of
the enthalpy change for the dissolution of CuCl(s) ? - Correct Answer A.
The value of the enthalpy change for the dissolution of CuCl(s) cannot be predicted from the particle
diagram because it fails to illustrate the amount of energy required to overcome the forces between
solute particles and between solvent particles.
The graph above represents the data collected under certain conditions for the decomposition of
N2O4(g) according to the chemical equation above. Based on the graph, at approximately which time is
equilibrium established? - Correct Answer D.
At time D, because there are no observable changes in [NO2] and [N2O4].
A sample of acetone is placed into a container. The container is sealed and attached to a pressure sensor,
as shown in the diagram above. The container is allowed to sit on the lab table for a few minutes as the
pressure in the container is monitored at regular intervals. At the end of 2.00 minutes, some acetone
liquid remains in the container. Which of the following best explains the pressure data presented in the
table above? - Correct Answer C.
The acetone vaporizes from the liquid at a constant rate and the rate of condensation increases until it
becomes equal to the rate of evaporation and the pressure stays constant.
A sample of pure NO2(g) in a sealed tube at 20°C is placed in a temperature bath at 30°C. Observations
of changes in the color, pressure, and mass of the mixture are recorded as a function of time. Which of
, the following is an observation that would best support the claim that the reaction represented above
has reached equilibrium at 30°C? - Correct Answer C.
The total pressure of the system decreases then reaches a constant value because at equilibrium the
amounts of reactant and product no longer change.
When AgCl(s) is placed in water, it dissolves according to the chemical equation above. The particle
diagram above was proposed to represent an aqueous solution in which AgCl(s) is in equilibrium with its
ions. Which of the following best explains whether or not the diagram provides a good representation of
this dynamic equilibrium at the microscopic level? - Correct Answer D.
It is not a good representation because it does not illustrate the dynamic equilibrium in which the rates
of the forward and reverse reactions are equal.
The particle diagram above shows the system represented by the equation 2X(g)+Y2(g)⇄2XY(g) . Which
of the following explains whether the particle diagram indicates that the system is at equilibrium? -
Correct Answer A.
The particle diagram does not indicate that the system is at equilibrium because it shows the system only
at one point in time.
The particle diagrams above show the changes that occurred after an equimolecular mixture of X(g) and
Y(g) was placed inside a rigid container at constant temperature. Which of the following statements is be
best supported by the particle diagrams? - Correct Answer C.
The forward reaction has a faster rate than the reverse reaction between 0s and 300s because more
products were being formed.
In an experiment involving the reaction shown above, a sample of pure HI was placed inside a rigid
container at a certain temperature. The table above provides the initial and equilibrium concentrations
for some of the substances in the reaction. Based on the data, which of the following is the value of the
equilibrium constant (Keq) for the reaction, and why? - Correct Answer C.
Keq=1.6×10−2, because [I2]eq=[H2]eq
Which of the following indicates the equilibrium value of PCl2 and the approximate value of the
equilibrium constant Kp ? - Correct Answer C.
PCl2=0.20atm and Kp=20.
Questions With High Ratings
Which of the following changes to the particle diagram will best represent the effect of adding 1.0mL of
4MNaCl to the solution? - Correct Answer B.
Some of the Cu+ and Cl− ions combine to form CuCl(s) because the molar solubility will be lower than
4×10−4M
Which of the following best explains what the particle diagram is able to show about the entropy change
for the dissolution of CuCl(s) in pure water? - Correct Answer A.
The particle diagram shows that the dissociation of CuCl(s) into ions contributes to an increase in the
entropy for the dissolution.
Which of the following best explains whether or not the particle diagram can predict the relative value of
the enthalpy change for the dissolution of CuCl(s) ? - Correct Answer A.
The value of the enthalpy change for the dissolution of CuCl(s) cannot be predicted from the particle
diagram because it fails to illustrate the amount of energy required to overcome the forces between
solute particles and between solvent particles.
The graph above represents the data collected under certain conditions for the decomposition of
N2O4(g) according to the chemical equation above. Based on the graph, at approximately which time is
equilibrium established? - Correct Answer D.
At time D, because there are no observable changes in [NO2] and [N2O4].
A sample of acetone is placed into a container. The container is sealed and attached to a pressure sensor,
as shown in the diagram above. The container is allowed to sit on the lab table for a few minutes as the
pressure in the container is monitored at regular intervals. At the end of 2.00 minutes, some acetone
liquid remains in the container. Which of the following best explains the pressure data presented in the
table above? - Correct Answer C.
The acetone vaporizes from the liquid at a constant rate and the rate of condensation increases until it
becomes equal to the rate of evaporation and the pressure stays constant.
A sample of pure NO2(g) in a sealed tube at 20°C is placed in a temperature bath at 30°C. Observations
of changes in the color, pressure, and mass of the mixture are recorded as a function of time. Which of
, the following is an observation that would best support the claim that the reaction represented above
has reached equilibrium at 30°C? - Correct Answer C.
The total pressure of the system decreases then reaches a constant value because at equilibrium the
amounts of reactant and product no longer change.
When AgCl(s) is placed in water, it dissolves according to the chemical equation above. The particle
diagram above was proposed to represent an aqueous solution in which AgCl(s) is in equilibrium with its
ions. Which of the following best explains whether or not the diagram provides a good representation of
this dynamic equilibrium at the microscopic level? - Correct Answer D.
It is not a good representation because it does not illustrate the dynamic equilibrium in which the rates
of the forward and reverse reactions are equal.
The particle diagram above shows the system represented by the equation 2X(g)+Y2(g)⇄2XY(g) . Which
of the following explains whether the particle diagram indicates that the system is at equilibrium? -
Correct Answer A.
The particle diagram does not indicate that the system is at equilibrium because it shows the system only
at one point in time.
The particle diagrams above show the changes that occurred after an equimolecular mixture of X(g) and
Y(g) was placed inside a rigid container at constant temperature. Which of the following statements is be
best supported by the particle diagrams? - Correct Answer C.
The forward reaction has a faster rate than the reverse reaction between 0s and 300s because more
products were being formed.
In an experiment involving the reaction shown above, a sample of pure HI was placed inside a rigid
container at a certain temperature. The table above provides the initial and equilibrium concentrations
for some of the substances in the reaction. Based on the data, which of the following is the value of the
equilibrium constant (Keq) for the reaction, and why? - Correct Answer C.
Keq=1.6×10−2, because [I2]eq=[H2]eq
Which of the following indicates the equilibrium value of PCl2 and the approximate value of the
equilibrium constant Kp ? - Correct Answer C.
PCl2=0.20atm and Kp=20.
