PRE-AP CHEMISTRY
Test Booklet
Unit 4 Learning Checkpoint 2
1.
Which of the following best models a weak acid in aqueous solution? (Water molecules are not included.)
(A)
(B)
(C)
More Acid particles are formed in this H+
(D)
2.
3.
Sulfur oxides and nitrogen oxides are pollutants that are produced when fossil fuels are burned. Sulfur oxides and
nitrogen oxides react with water in the atmosphere, which leads to the production of sulfuric acid and nitric acid,
and thus acid rain. Rainwater is naturally acidic and has a
of approximately
, but acid rain has a lower
,
sometimes below . Which of the following correctly compares the concentration of
in acid rain with a
of
and the concentration of
in rain that is naturally acidic and has a
of
?
(A)
concentration in the acid rain is a factor of
The
that is naturally acidic.
times higher than the
(B)
concentration in the acid rain is
The
naturally acidic.
(C)
The
concentration in the acid rain is
naturally acidic.
times higher than the
concentration in the rain that is
(D)
The
concentration in the acid rain is
naturally acidic.
times higher than the
concentration in the rain that is
times higher than the
concentration in the rain
concentration in the rain that is
A student is given a concentrated solution that is supposed to contain vinegar, a weak acid. Which of the following
experimental tests would best support the claim that the solution is a weak acid rather than a strong acid?
Copyright © 2023. The College Board. These materials are part of a College Board program. Use or distribution of these materials
online or in print beyond your school’s participation in the program is prohibited.
Pre-AP Chemistry
Page 1 of 5
Test Booklet
Unit 4 Learning Checkpoint 2
(A) Measure the
of the solution; if the value is above , then the solution is a weak acid.
(B)
Measure the
of the solution; if the value is below , then the solution is a weak acid.
(C)
Measure the electrical conductivity of the solution; if the solution is a good conductor, then the solution is a
weak acid.
(D)
Measure the electrical conductivity of the solution; if the solution is a poor conductor, then the solution is a
weak acid.
Less H+ bonding---> weak acid.
4.
Which of the following is the approximate
(A)
of the solution represented in the particle diagram?
3 positive and 3 negative--> Cancel out-ish and cannot be zero either.
(B)
(C)
(D)
5.
A student combines equal volumes of
aqueous solutions of hydrochloric acid and sodium hydroxide. The
equation for the reaction is shown. The student places the resulting solution in an evaporating dish and heats it on a
hot plate. Which of the following substances will remain in the evaporating dish once all the water has evaporated?
(A)
(B)
(C)
(D)
Page 2 of 5
NaCl is table salt and when aqueous and evaporated, it will crystallize and the H20 will
evaporate.
Pre-AP Chemistry
Copyright © 2023. The College Board. These materials are part of a College Board program. Use or distribution of these materials
online or in print beyond your school’s participation in the program is prohibited.
Test Booklet
Unit 4 Learning Checkpoint 2
Exothermic reaction means that energy is released, like nuclear fission.
6.
For the given hypothetical reaction, which of the following best describes how the temperature changes as the
reaction progresses and why?
(A)
The temperature increases because more energy is released when the new bonds in the product form than is
absorbed when the bonds in the reactant break.
(B)
The temperature increases because more energy is absorbed when the new bonds in the product form than is
released when the bonds in the reactant break.
(C)
The temperature decreases because more energy is released when the new bonds in the product form than is
absorbed when the bonds in the reactant break.
(D)
The temperature decreases because more energy is absorbed when the new bonds in the product form than is
released when the bonds in the reactant break.
7.
A student conducts a series of experiments involving the reaction of
with
. Particle representations of
three different reaction conditions in containers of equal volume are shown. For each Figure, circle the correct rate
description: fastest, intermediate, or slowest to rank the order of reaction rates.
Figure 1: Slowest | Intermediate | Fastest
Figure 2: Slowest | Intermediate | Fastest
Low temp
High temp, but more bonds to break, so more energy
High temp and less bonds
Figure 3: Slowest | Intermediate | Fastest
Copyright © 2023. The College Board. These materials are part of a College Board program. Use or distribution of these materials
online or in print beyond your school’s participation in the program is prohibited.
Pre-AP Chemistry
Page 3 of 5
Test Booklet
Unit 4 Learning Checkpoint 2
8.
Certain types of sealed packets can be used to warm up or cool down objects. Some packets are activated by
unsealing them and exposing their contents to air. To investigate the reaction that occurs inside a packet, a student
weighs the materials in the packet, places those materials in a small beaker, surrounds the beaker with a larger
beaker of water, and adds a thermometer to the water, as shown in the figure. The student records the following data
and then measures a final weight upon completion of the experiment.
Initial Value
Final Value
Mass of packet mixture
Temperature of water
Temp of water increased
Which of the following statements about the chemical reaction is best supported using the data from the
experiment?
(A) The reaction is exothermic because the temperature of the water increased during the reaction.
(B)
The reaction is exothermic because the mass of the mixture increased during the reaction.
(C)
The reaction is endothermic because the temperature of the water increased during the reaction.
(D) The reaction is endothermic because the mass of the mixture increased during the reaction.
9.
Temperature of
Temperature of
mixing
before mixing
before
Temperature of solution after mixing
A student performs a calorimetry experiment. The student combines
of
with
. Data are given in the table. The value of for the experiment is closest to which of the
following? (Assume that the heat capacity of the solution is the same as the heat capacity of water.)
Page 4 of 5
Pre-AP Chemistry
of
Copyright © 2023. The College Board. These materials are part of a College Board program. Use or distribution of these materials
online or in print beyond your school’s participation in the program is prohibited.
Q=MC^T
Test Booklet
Unit 4 Learning Checkpoint 2
(A)
(B)
(C)
(D)
10.
Two
solutions are represented in the particle diagrams. Select the solution with the higher pH. Then, select the
reasoning that best supports the claim.
(A) Solution A
(B)
Solution B
(C)
It has a lower concentration of H+ ions.
(D) It has a higher concentration of H+ ions.
11.
The diagram shows three different acid solutions of equal volume. Which of the following identifies the strongest
acid and explains why the acid is strongest?
(A) Acid , because it contains the fewest conjugate base particles.
(B)
Acid , because it has the greatest percent dissociation.
(C)
Acid , because it contains the greatest number of acid particles.
(D) Acids , , and
are all equal in strength, because they all dissociate to form
Copyright © 2023. The College Board. These materials are part of a College Board program. Use or distribution of these materials
online or in print beyond your school’s participation in the program is prohibited.
Pre-AP Chemistry
and
.
Page 5 of 5