Ap chemistry Unit 7 Progress Check; MCQ Test 2023
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? - 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? - 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? - 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? - 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? - 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? - 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? - 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 ? - ANSWER C.
PCl2=0.20atm and Kp=20.
The diagram above represents the equilibrium between two isomers of 2-butene.
The equilibrium constant, Kc, is 1.2 at a certain temperature. Two identical vessels
each contain an equilibrium mixture of the two gases at that temperature. The
concentration of cis-2-butene in the second vessel is twice the concentration in the
first vessel. What is the concentration of trans-2-butene in the second vessel
compared to that in the first vessel? - ANSWER C.
Twice the concentration of that in the first vessel
The equilibrium reaction in 0.100M HBrO(aq) at equilibrium is represented by the
equation above. Based on the magnitude of the equilibrium constant, which of the
following correctly compares the equilibrium concentrations of substances
involved in the reaction, and why? - ANSWER B.
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? - 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? - 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? - 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? - 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? - 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? - 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? - 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 ? - ANSWER C.
PCl2=0.20atm and Kp=20.
The diagram above represents the equilibrium between two isomers of 2-butene.
The equilibrium constant, Kc, is 1.2 at a certain temperature. Two identical vessels
each contain an equilibrium mixture of the two gases at that temperature. The
concentration of cis-2-butene in the second vessel is twice the concentration in the
first vessel. What is the concentration of trans-2-butene in the second vessel
compared to that in the first vessel? - ANSWER C.
Twice the concentration of that in the first vessel
The equilibrium reaction in 0.100M HBrO(aq) at equilibrium is represented by the
equation above. Based on the magnitude of the equilibrium constant, which of the
following correctly compares the equilibrium concentrations of substances
involved in the reaction, and why? - ANSWER B.
