AP CHEMISTRY
Test Booklet
5.1 Reaction rate
1.
Which of the following will most likely increase the rate of the reaction represented above?
(A) Decreasing the temperature of the reaction system
(B)
Adding a heterogeneous catalyst to the reaction system
(C)
Increasing the volume of the reaction vessel using a piston
(D) Removing some H2(g) from the reaction system
AP Chemistry
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Test Booklet
5.1 Reaction rate
An experiment is performed to measure the mass percent of
in eggshells. Five different samples of
of known mass react with an excess of
in identical sealed, rigid reaction vessels. The
pressure of the gas produced is measured with a pressure gauge attached to the reaction vessel. Since the reaction is
exothermic, the reaction system is cooled to its original temperature before the pressure is recorded. The experimental
data are used to create the calibration line below.
The experiment is repeated with an eggshell sample, and the experimental data are recorded in the table below.
Mass of eggshell sample
Pressure prior to reaction
Pressure at completion of reaction
2.
Which of the following modifications will increase the rate of the reaction the most?
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AP Chemistry
Test Booklet
5.1 Reaction rate
(A) Using
instead of
(B)
Cooling the
(C)
Reducing the volume of the reaction vessel
to a lower temperature than it was in the original experiment
(D) Using eggshells that are more finely powdered than those used in the original experiment
3.
Two solid reactants of varying particle size are combined in a vessel. Assuming that the same mass of each reactant
is used in each case, which of the following represents the conditions that will result in the fastest reaction rate?
(A)
(B)
(C)
(D)
Cu(s) + 4 HNO3(aq) → Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l)
Each student in a class placed a 2.00 g sample of a mixture of Cu and Al in a beaker and placed the beaker in a fume
hood. The students slowly poured 15.0 mL of 15.8 M HNO3(aq) into their beakers. The reaction between the copper in the
mixture and the HNO3(aq) is represented by the equation above. The students observed that a brown gas was released
from the beakers and that the solutions turned blue, indicating the formation of Cu2+(aq). The solutions were then diluted
with distilled water to known volumes.
4.
In one student’s experiment the reaction proceeded at a much slower rate than it did in the other students’
experiments. Which of the following could explain the slower reaction rate?
(A) In the student’s sample the metal pieces were much smaller than those in the other students’ samples.
(B)
The student heated the reaction mixture as the HNO3(aq) was added.
(C)
The student used a 1.5 M solution of HNO3(aq) instead of a 15.8 M solution of HNO3(aq).
(D)
The student used a 3.00 g sample of the mixture instead of the 2.00 g sample that was used by the other
students.
AP Chemistry
Page 3 of 25
Test Booklet
5.1 Reaction rate
5.
Directions: For parts of the free-response question that require calculations, clearly show the method used
and the steps involved in arriving at your answers. You must show your work to receive credit for your
answer. Examples and equations may be included in your answers where appropriate.
An unknown gas,
equation.
, reacts with fluorine gas to form the compound
A series of experimental trials were performed at
Data from the trials are shown below.
Initial
(
to determine the rate law expression for the reaction.
Initial
)
(
, as represented by the following
Initial Rate of Appearance of
)
Trial 1
1500
1500
Trial 2
3000
1500
Trial 3
1500
3000
(
(a) A student claims that the reaction is first order with respect to
answer using the data above.
)
. Do you agree or disagree? Justify your
Please respond on separate paper, following directions from your teacher.
(b) What is the initial rate of disappearance of
in trial 3? Justify your answer.
Please respond on separate paper, following directions from your teacher.
(c) A student claims that if element is in group 18, then the molecular geometry of
theory.
Do you agree or disagree with the student? Justify your answer in terms of
is square planar.
Please respond on separate paper, following directions from your teacher.
The particulate model shown below represents the moles of particles present in the container after
Page 4 of 25
AP Chemistry
and
Test Booklet
5.1 Reaction rate
have reacted in a different experiment. Assume that each particle in the diagram represents one mole of the
respective substance. (Note: The box corresponding to “Before Reaction” is intentionally left blank.)
(d) If the total pressure at the end of the reaction is
, what is the partial pressure of
?
Please respond on separate paper, following directions from your teacher.
(e) Assuming that only and
are present in the container before the reaction, determine the number of moles
that were present in the initial reaction mixture.
of and
Please respond on separate paper, following directions from your teacher.
The equation and enthalpy change for the reaction between
(f) If
released?
of
and
is produced when equimolar amounts of
are given below.
and
react, how much heat is
Please respond on separate paper, following directions from your teacher.
Fluorine can also react with another gas,
(g) The student claims that the
disagree? Justify your answer.
, according to the following equation.
bond energy is greater than the
bond energy. Do you agree or
AP Chemistry
Page 5 of 25
Test Booklet
5.1 Reaction rate
Please respond on separate paper, following directions from your teacher.
While investigating the properties of other diatomic molecules, the student finds the diagram below, which shows
the potential energy of two iodine atoms versus the distance between their nuclei. The student also finds that the
bond energy is slightly less than the
bond energy. The student incorrectly sketches the potential
energy curve for two fluorine atoms, shown by the dotted line in the diagram.
(h) Explain the error with the student’s sketch for
.
Please respond on separate paper, following directions from your teacher.
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AP Chemistry
Test Booklet
5.1 Reaction rate
6.
Directions: For parts of the free-response question that require calculations, clearly show the method used
and the steps involved in arriving at your answers. You must show your work to receive credit for your
answer. Examples and equations may be included in your answers where appropriate.
An unknown gas,
equation.
, reacts with fluorine gas to form the compound
A series of experimental trials were performed at
Data from the trials are shown below.
Initial
(
to determine the rate law expression for the reaction.
Initial
)
(
, as represented by the following
Initial Rate of Appearance of
)
Trial 1
3000
3000
Trial 2
6000
3000
Trial 3
3000
6000
(
(a) A student claims that the reaction is first order with respect to
answer using the data above.
)
. Do you agree or disagree? Justify your
Please respond on separate paper, following directions from your teacher.
(b) What is the initial rate of disappearance of
in trial 1? Justify your answer.
Please respond on separate paper, following directions from your teacher.
(c) A student claims that if element is in group 18, then the molecular geometry of
theory.
you agree or disagree with the student? Justify your answer in terms of
is tetrahedral. Do
Please respond on separate paper, following directions from your teacher.
The particulate model shown below represents the moles of particles present in the container after
AP Chemistry
and
Page 7 of 25
Test Booklet
5.1 Reaction rate
have reacted in a different experiment. Assume that each particle in the diagram represents one mole of the
respective substance. (Note: The box corresponding to “Before Reaction” is intentionally left blank.)
(d) If the total pressure at the end of the reaction is
, what is the partial pressure of
?
Please respond on separate paper, following directions from your teacher.
(e) Assuming that only and
are present in the container before the reaction, determine the number of moles
that were present in the initial reaction mixture.
of and
Please respond on separate paper, following directions from your teacher.
The equation and enthalpy change for the reaction between
(f) How much heat is released when
of
and
reacts with excess
are given below.
?
Please respond on separate paper, following directions from your teacher.
Fluorine can also react with another gas,
(g) The student claims that the
disagree? Justify your answer.
Page 8 of 25
AP Chemistry
, according to the following equation.
bond energy is greater than the
bond energy. Do you agree or
Test Booklet
5.1 Reaction rate
Please respond on separate paper, following directions from your teacher.
While investigating the properties of other diatomic molecules, the student finds the diagram below, which shows
the potential energy of two nitrogen atoms versus the distance between their nuclei. The student incorrectly
sketches the potential energy curve for two fluorine atoms, shown by the dotted line in the diagram.
(h) Explain the error with the student’s sketch for
.
Please respond on separate paper, following directions from your teacher.
AP Chemistry
Page 9 of 25
Test Booklet
5.1 Reaction rate
7.
Directions: For parts of the free-response question that require calculations, clearly show the method used
and the steps involved in arriving at your answers. You must show your work to receive credit for your
answer. Examples and equations may be included in your answers where appropriate.
An unknown gas,
equation.
, reacts with fluorine gas to form the compound
A series of experimental trials were performed at
Data from the trials are shown below.
Initial
(
to determine the rate law expression for the reaction.
Initial
)
(
, as represented by the following
Initial Rate of Appearance of
)
Trial 1
3000
3000
Trial 2
6000
3000
Trial 3
3000
6000
(a) A student claims that the reaction is second order with respect to
your answer using the data above.
(
)
. Do you agree or disagree? Justify
Please respond on separate paper, following directions from your teacher.
(b) What is the initial rate of disappearance of
in trial 3? Justify your answer.
Please respond on separate paper, following directions from your teacher.
(c) A student claims that if element is in group 16, then the molecular geometry of
theory.
agree or disagree with the student? Justify your answer in terms of
Please respond on separate paper, following directions from your teacher.
Page 10 of 25
AP Chemistry
is see-saw. Do you
Test Booklet
5.1 Reaction rate
The particulate model shown below represents the moles of particles present in the container after
and
have reacted in a different experiment. Assume that each particle in the diagram represents one mole of the
respective substance. (Note: The box corresponding to “Before Reaction” is intentionally left blank.)
(d) If the total pressure at the end of the reaction is
, what is the partial pressure of
?
Please respond on separate paper, following directions from your teacher.
are present in the container before the reaction, determine the number of moles
(e) Assuming that only and
of and
that were present in the initial reaction mixture.
Please respond on separate paper, following directions from your teacher.
The equation and enthalpy change for the reaction between
(f) How much heat is released when
of
and
reacts with excess
are given below.
?
Please respond on separate paper, following directions from your teacher.
Fluorine can also react with another gas,
(g) The student claims that the
disagree? Justify your answer.
, according to the following equation.
bond energy is less than the
bond energy. Do you agree or
AP Chemistry
Page 11 of 25
Test Booklet
5.1 Reaction rate
Please respond on separate paper, following directions from your teacher.
While investigating the properties of other diatomic molecules, the student finds the following diagram, which
shows the potential energy of two iodine atoms versus the distance between their nuclei. The student also finds
bond energy is slightly less than the
bond energy. The student incorrectly sketches the
that the
potential energy curve for two fluorine atoms, shown by the dotted line in the diagram.
(h) Explain the error with the student’s sketch for
.
Please respond on separate paper, following directions from your teacher.
Page 12 of 25
AP Chemistry
Test Booklet
5.1 Reaction rate
8.
Directions: For parts of the free-response question that require calculations, clearly show the method used
and the steps involved in arriving at your answers. You must show your work to receive credit for your
answer. Examples and equations may be included in your answers where appropriate.
An unknown gas,
equation.
, reacts with fluorine gas to form the compound
A series of experimental trials were performed at
Data from the trials are shown below.
Initial
(
to determine the rate law expression for the reaction.
Initial
)
(
, as represented by the following
Initial Rate of Appearance of
)
Trial 1
3000
3000
Trial 2
6000
3000
Trial 3
3000
6000
(
(a) A student claims that the reaction is second order with respect to
answer using the data above.
)
. Do you agree or disagree? Justify your
Please respond on separate paper, following directions from your teacher.
(b) What is the initial rate of disappearance of
in trial 2? Justify your answer.
Please respond on separate paper, following directions from your teacher.
(c) A student claims that if element is in group 16, then the molecular geometry of
theory.
you agree or disagree with the student? Justify your answer in terms of
is tetrahedral. Do
Please respond on separate paper, following directions from your teacher.
The particulate model shown below represents the moles of particles present in the container after
AP Chemistry
and
Page 13 of 25
Test Booklet
5.1 Reaction rate
have reacted in a different experiment. Assume that each particle in the diagram represents one mole of the
respective substance. (Note: The box corresponding to “Before Reaction” is intentionally left blank.)
(d) If the total pressure at the end of the reaction is
, what is the partial pressure of
?
Please respond on separate paper, following directions from your teacher.
(e) Assuming that only and
are present in the container before the reaction, determine the number of moles
that were present in the initial reaction mixture.
of and
Math output error
Please respond on separate paper, following directions from your teacher.
The equation and enthalpy change for the reaction between
(f) How much heat is released when
of
and
are given below.
reacts with excess
?
Please respond on separate paper, following directions from your teacher.
Fluorine can also react with another gas,
(g) The student claims that the
disagree? Justify your answer.
Page 14 of 25
AP Chemistry
, according to the following equation.
bond energy is less than the
bond energy. Do you agree or
Test Booklet
5.1 Reaction rate
Please respond on separate paper, following directions from your teacher.
While investigating the properties of other diatomic molecules, the student finds the diagram below, which shows
the potential energy of two nitrogen atoms versus the distance between their nuclei. The student incorrectly
sketches the potential energy curve for two fluorine atoms, shown by the dotted line in the diagram.
(h) Explain the error with the student’s sketch for
.
Please respond on separate paper, following directions from your teacher.
sample of
A
9.
was placed in a solution of
, where it reacted completely.
In a third experiment,
samples of
are placed in excess
of various concentrations:
,
,
, and
. The reactions are run in successive order from
to
, and the time required for each reaction to go to completion is recorded. As the concentration of
increases from
to
, which of the following is the expected result?
(A) The reaction time increases, and the rate of the reaction decreases.
(B)
The reaction time decreases, and the rate of the reaction increases.
(C)
Both the reaction time and the rate of the reaction increase.
(D) Both the reaction time and the rate of the reaction decrease.
AP Chemistry
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Test Booklet
5.1 Reaction rate
10.
H3AsO4 + 3 I– + 2 H3O+ → H3AsO3 + I3– + H2O
The oxidation of iodide ions by arsenic acid in acidic aqueous solution occurs according to the stoichiometry shown
above. The experimental rate law of the reaction is:
Rate = k[H3AsO4] [I–] [H3O+]
According to the rate law for the reaction, an increase in the concentration of hydronium ion has what effect on this
reaction?
(A) The rate of reaction increases.
(B)
The rate of reaction decreases.
(C)
The value of the equilibrium constant increases.
(D) The value of the equilibrium constant decreases.
(E)
11.
Neither the rate nor the value of the equilibrium constant is changed.
Step 1: Cl(g) + O3(g) → ClO(g) + O2(g)
Step 2: ClO(g) + O(g) → Cl(g) + O2(g)
A proposed mechanism for destruction of ozone gas in the stratosphere is represented above. Which of the
following is evidence that the mechanism is occurring?
(A) The presence of Cl(g) increases the rate of the overall reaction.
(B)
The presence of Cl(g) decreases the rate of the overall reaction.
(C)
The presence of Cl(g) increases the equilibrium constant of the overall reaction.
(D) The presence of Cl(g) decreases the equilibrium constant of the overall reaction.
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AP Chemistry
Test Booklet
5.1 Reaction rate
12.
C2H4(g) + H2(g)
C2H6(g)
C2H4(g) is reduced by H2(g) in the presence of a solid platinum catalyst, as represented by the equation above.
Factors that could affect the rate of the reaction include which of the following?
I. Changes in the partial pressure of H2(g)
II. Changes in the particle size of the platinum catalyst
III. Changes in the temperature of the reaction system
(A) III only
(B)
I and II only
(C)
I and III only
(D) II and III only
(E)
13.
I, II, and III
5 H2O2(aq) + 2 MnO4-(aq) + 6 H+(aq) → 2 Mn2+(aq) + 8 H2O(l) + 5 O2(g)
In a titration experiment, H2O2(aq) reacts with aqueous MnO4-(aq) as represented by the equation above. The dark
purple KMnO4 solution is added from a buret to a colorless, acidified solution of H2O2(aq) in an Erlenmeyer flask.
(Note: At the end point of the titration, the solution is a pale pink color.)
At a certain time during the titration, the rate of appearance of O2(g) was 1.0 x 10-3 mol/(L⋅s). What was the rate of
disappearance of MnO4- at the same time?
(A) 6.0 x 10-3 mol/(L⋅s)
(B)
4.0 x 10-3 mol/(L⋅s)
(C)
6.0 x 10-4 mol/(L⋅s)
(D) 4.0 x 10-4 mol/(L⋅s)
14.
A kinetics experiment is set up to collect the gas that is generated when a sample of chalk, consisting primarily of
solid CaCO3, is added to a solution of ethanoic acid, CH3COOH. The rate of reaction between CaCO3 and
CH3COOH is determined by measuring the volume of gas generated at 22oC and 1 atm as a function of time. Which
of the following experimental conditions is most likely to increase the rate of gas production?
(A) Decreasing the volume of ethanoic acid solution used in the experiment
(B)
Decreasing the concentration of the ethanoic acid solution used in the experiment
(C)
Decreasing the temperature at which the experiment is performed
(D) Decreasing the particle size of the CaCO3 by grinding it into a fine powder
AP Chemistry
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Test Booklet
5.1 Reaction rate
15.
A student performed an experiment to study the factors that affect the rate of the first-order catalytic decomposition
of
, represented above.
The student monitored the volume of
produced over time as the reaction proceeded. The data from two trials
are plotted in the graph above. Which of the following best explains the results of trial compared with those of
trial ?
(A) The reaction temperature in trial
was higher than it was in trial .
(B)
The volume of the reaction vessel was larger in trial
than it was in trial .
(C)
The student used a smaller amount of
compared with that used in trial .
(D) The concentration of
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AP Chemistry
in trial
was lower in trial
than it was in trial .
Test Booklet
5.1 Reaction rate
A 0.35 g sample of Li(s) is placed in an Erlenmeyer flask containing 100 mL of water at 25°C. A balloon is placed over
the mouth of the flask to collect the hydrogen gas that is generated.
After all of the Li(s) has reacted with H2O(l), the solution in the flask is added to a clean, dry buret and used to titrate an
aqueous solution of a monoprotic acid. The pH curve for this titration is shown in the diagram below
16.
Which of the following changes will most likely increase the rate of reaction between Li(s) and water?
(A) Using 125 mL of water instead of 100 mL
(B)
Using a 0.25 g sample of Li(s) instead of a 0.35 g sample
(C)
Using a 0.35 g sample of Li(s) cut into small pieces
(D) Decreasing the water temperature before adding the Li(s)
AP Chemistry
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Test Booklet
5.1 Reaction rate
17.
Reactant
Initial Concentration
The oxidation of
producing
is represented by the chemical equation shown above. The initial
and
are given in the table above. The changes in the concentration of
as a
concentrations of
function of time are shown in the following graph.
Under the same conditions, one of the following graphs represents the changes in the concentration of
the same period of time.
Which graph best represents the changes in concentration of
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AP Chemistry
, and why?
over
Test Booklet
5.1 Reaction rate
(A)
consumption is half the rate at which
Graph 1, because the rate of
react for each molecule of
that reacts.
is consumed; two molecules of
(B)
Graph 1, because
molecules are consumed at a slower rate at the beginning of the reaction when there are
not as many molecules of
produced.
(C)
Graph 2, because there is a large excess of
over time.
(D)
Graph 2, because a collision between three molecules to form a product has a low probability and the
concentration of
will remain relatively constant.
molecules and its concentration will not change drastically
18.
Two samples of Mg(s) of equal mass were placed in equal amounts of HCI(aq) contained in two separate reaction
vessels. Particle representations of the mixing of Mg(s) and HCI(aq) in the two reaction vessels are shown in Figure
1 and Figure 2 above. Water molecules are not included in the particle representations. Which of the reactions will
initially proceed faster, and why?
(A) The reaction in Figure 1, because the atoms of Mg are more concentrated than those in Figure 2
(B)
The reaction in Figure 1, because the Mg(s) in Figure 1 has a larger mass than the Mg(s) in Figure 2
(C)
The reaction in Figure 2, because more Mg atoms are exposed to HCI(aq) in Figure 2 than in Figure 1
(D) The reaction in Figure 2, because the Mg(s) in Figure 2 has less surface area than the Mg(s) in Figure 1
AP Chemistry
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Test Booklet
5.1 Reaction rate
19.
of
Initial Concentration
of
Initial Temperature
of Reactants
1
5.00
1.0
25.0
2
5.00
2.0
25.0
Experiment
Initial Mass
The initial rate of formation of
from the chemical reaction represented by the equation above was studied
in two separate experiments. The table above provides the experimental conditions used. If both experiments are
carried out with finely powdered samples of the solid and
of
, which experiment, if any, will
and why?
have the faster initial rate of formation of
(A)
The rate of formation of
will be the same because the mass of
used will be the same in both experiments.
(B)
will be the same because the surface area of the solid and the average
The rate of formation of
kinetic energy of the particles will be the same in both experiments.
(C)
(D)
Page 22 of 25
will be formed at a faster rate in experiment 2 because more
and the volume of
particles can react per unit time.
will be formed at a faster rate in experiment 1 because the proportion of
particles will be greater.
AP Chemistry
particles to
Test Booklet
5.1 Reaction rate
20.
The reaction between
and
is represented by the equation above. Two separate trials were
samples of the same mass, but one sample was a single piece of
, and one
carried out using
sample was composed of small pieces of
. The loss of mass of
as a function of time for
both trials is shown in the graph below.
Which of the curves,
(A) Curve
(B)
(C)
(D)
21.
or
, represents the reaction with small pieces of
, and why?
, because it shows that the reaction proceeded at a uniform rate.
Curve
, because it takes a shorter time for the reaction to go to completion due to the larger surface area of
.
Curve
, because it shows that the reaction proceeded at a nonuniform rate.
Curve
, because it takes a shorter time for the reaction to go to completion due to the larger surface area of
.
When the chemical reaction
disappearance of
is
conditions?
is carried out under certain conditions, the rate of
. What is the rate of disappearance of
under the same
AP Chemistry
Page 23 of 25
Test Booklet
5.1 Reaction rate
(A)
Because two molecules of
.
are consumed per molecule of
, the rate of disappearance of
is
(B)
Because two molecules of
.
are consumed per molecule of
, the rate of disappearance of
is
(C)
Because the rate depends on
(D)
Because the
and
, the rate of disappearance of
is under the same experimental conditions as
.
22.
is
.
, it is consumed at the same rate of
X(g) + 2 Y(g) → XY2(g)
In order to determine the order of the reaction represented above, the initial rate of formation of XY2 is measured
using different initial values of [X] and [Y]. The results of the experiment are shown in the table below.
In trial 2 which of the reactants would be consumed more rapidly, and why?
(A) X, because it has a higher molar concentration.
(B)
X, because the reaction is second order with respect to X.
(C)
Y, because the reaction is second order with respect to Y.
(D) Y, because the rate of disappearance will be double that of X.
23.
Relatively slow rates of chemical reaction are associated with which of the following?
(A) The presence of a catalyst
(B)
High temperature
(C)
High concentration of reactants
(D) Strong bonds in reactant molecules
(E)
24.
Low activation energy
A kinetics experiment is set up to collect the gas that is generated when a sample of chalk, consisting primarily of
solid CaCO3, is added to a solution of ethanoic acid, CH3COOH. The rate of reaction between CaCO3 and
CH3COOH is determined by measuring the volume of gas generated at 25oC and 1 atm as a function of time. Which
of the following experimental conditions is most likely to increase the rate of gas production?
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AP Chemistry
Test Booklet
5.1 Reaction rate
(A) Decreasing the volume of ethanoic acid solution used in the experiment
(B)
Decreasing the concentration of the ethanoic acid solution used in the experiment
(C)
Decreasing the temperature at which the experiment is performed
(D) Decreasing the particle size of the CaCO3 by grinding it into a fine powder
25.
X+2Y→Z+3Q
For the reaction represented above, the initial rate of decrease in [X] was 2.8 × 10-3 mol L-1 s-1. What was the initial
rate of decrease in [Y] ?
(A) 7.0 × 10-4 mol L-1 s-1
(B)
1.4 × 10-3 mol L-1 s-1
(C)
2.8 × 10-3 mol L-1 s-1
(D) 5.6 × 10-3 mol L-1 s-1
(E)
1.1 × 10-2 mol L-1 s-1
AP Chemistry
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