South Pasadena • AP Chemistry
Name
10 ▪ States of Matter
Period
Date
UNIT TEST
The following formulas may be helpful.
vrms =
3·R·T
MM
vA
=
vB
–
PRACTICE
MMB
MMA
Part 1 – Multiple Choice
You should allocate 25 minutes to finish this portion of the test. No calculator should be used. A periodic table
and data table will be provided. Select the answer that best responds to each question.
1. A crystalline solid displays the following
properties:
Has a melting point of 775°C.
Does not conduct electricity as a solid.
Is soluble in water.
Which of the following could be this solid?
(A) CaCl2
(B) Diamond
(C) Zn
(D) P4O10
2. Boron is introduced into a crystal of silicon, which
allows the silicon to significantly increase its
electrical conductivity. Which of the following
explains this result?
(A) Boron has a “sea of electrons” that allows
silicon to conduct electricity better.
(B) Boron has fewer valence electrons than
silicon, which creates positive holes that can
be filled to conduct electricity.
(C) Boron has more valence electrons than silicon,
so the excess electrons allow the material to
conduct electricity better.
(D) Boron’s electronegativity is high, so it pulls
electrons more strongly than silicon.
3. Which of the following substances would be
expected to have the highest melting point
temperature?
(A) Iodine, I2
(B) Mercury, Hg
(C) Silicon dioxide, SiO2
(D) Tetraphosphorous decoxide, P4O10
4. Consider the compounds, SO2, CO2, PbO2. When
listed in order of increasing strength of
interparticle forces, the list would be
(A) CO2 < SO2 < PbO2
(B) PbO2 < CO2 < SO2
(C) SO2 < PbO2 < CO2
(D) CO2 < PbO2 < SO2
nucleotide
enzyme
5. The figure above shows the side of an enzyme
(shown in solid and dashed lines) with specific
amino acids bound to a nucleotide. What is the
interaction that shows how the nucleotide and
enzyme bind shown at the indicated arrow?
(A) Hydrogen bonding
(B) Hydrophillic interactions
(C) Hydrophobic interactions
(D) Ion-dipole interaction
6. A typical phase diagram for a substance is given
below. At what point on the diagram do gas and
liquid exist at equilibrium?
10. What is the ratio of the root mean square speed of
He (g) at 100°C to that of He (g) at 50°C?
323
(A)
373
Pressure
(B)
Temperature
(A) A
(B) B
(C) C
(D) D
7. A 50 mL sample of an unknown liquid is placed in
an evacuated closed container and allowed to
reach equilibrium. Which of the following
increases the vapor pressure of the liquid in the
container?
(A) Increase the temperature of the sample.
(B) Add more of the liquid to the container.
(C) Transfer the liquid to a container with twice
the volume.
(D) Pump an inert gas into the container.
8. Which of the following properties is expected to
be lower for hydrazine (N2H4) than for nitrogen
tetroxide (N2O4)?
(A) Enthalpy of Vaporization (∆Hvap)
(B) Normal Boiling Point
(C) Vapor Pressure
(D) All of these are expected to be higher for
hydrazine
9. A 0.50 mol sample of F2 (g) is introduced into an
evacuated container. In a two-stepped process, the
Kelvin temperature of the sample is tripled, and
then the volume is halved. Which of the following
one-step changes to the original sample would
result in the same final pressure as the two-stepped
process?
(A) Add 1.5 mol F2 (g)
(B) Add 2.0 mol F2 (g)
(C) Add 2.5 mol F2 (g)
(D) Add 3.0 mol F2 (g)
373
323
2
(C) 1
2
(D) 1
11. Equal masses of helium and neon gases are placed
in a container at 25°C. Which of the following are
true?
I. The partial pressures of helium and neon
are equal.
II. The average kinetic energy of helium and
neon are equal.
III. The room mean square speed of helium
and neon are equal.
(A) I only.
(B) II only.
(C) II and III only.
(D) I, II, and III.
12. What is the molar mass of a gas if, at STP, it has a
density of 2.86 g/L?
(A) 8 g/mol
(B) 16 g/mol
(C) 32 g/mol
(D) 64 g/mol
13. He gas is considered the most ideal of all real
gases. Which reason(s) account for this
statement?
I. He has a filled electron shell.
II. He exhibits very weak IMFs.
III. He has a very small atomic radius.
(A) I only
(B) I and II only
(C) II and III only
(D) I, II and III
14. Compared to pure water, salt water has a higher
(A) Boiling point temperature
(B) Freezing point temperature
(C) Vapor pressure
(D) None of these are higher for salt water than for
water
15. Green spinach leaves were ground up and mixed
with ethyl alcohol. A sample of this mixture was
then placed on chromatography paper, which is
placed in a test tube with a small amount of ethyl
alcohol. The results of the experiment after 20
minutes is shown below.
Which of the following might be concluded about
the pigment circled that traveled 5.5 cm?
(A) It is less soluble in ethyl alcohol and less
adsorptive to the chromatography paper than
the other pigments.
(B) It is less soluble in ethyl alcohol and more
adsorptive to the chromatography paper than
the other pigments.
(C) It is more soluble in ethyl alcohol and less
adsorptive to the chromatography paper
than the other pigments.
(D) It is more soluble in ethyl alcohol and more
adsorptive to the chromatography paper than
the other pigments.
Part 2 – Free Response
You should allocate 30 minutes to finish this portion of the test. You may use a scientific calculator. A periodic
table and data table will be provided. Respond to each part of the questions completely. Be sure to show your
work clearly for questions that involve calculations.
(From AP Chemistry 1994 #3)
16. A student collected a sample of hydrogen gas by the displacement of water as
shown by the diagram above. The relevant data are given in the following table.
(a) Calculate the number of moles of hydrogen gas collected.
PH2 = Patm – Pvap,H2O = 745 mmHg – 23.8 mmHg = 721 mmHg
PH2·V
nH2 =
=
R·T
(0.949 atm) 90.0 mL
0.08206
1L
1000 mL
atm·L
(25 + 273 K)
mol·K
1 atm
= 0.949 atm
760 mmHg
= 0.00349 mol
(b) Calculate the number of molecules of water vapor in the sample of gas.
1 atm
1L
745 mmHg
90.0 mL
760
mmHg
1000
mL
PH2O·V
nH2O =
=
= 0.00361 mol H2O
R·T
atm·L
0.08206
(25 + 273 K)
mol·K
6.022 × 1023 molecules H2O
NH2O = 0.00361 mol H2O
= 2.17 × 1021 molecules H2O
1 mol H2O
(c) Calculate the ratio of the average speed of the hydrogen molecules to the average speed of the water
vapor molecules in the sample.
vH2
MMH2O
18.016 g/mol 2.99
=
=
=
vH2O
MMH2
2.016 g/mol
1
(d) Which of the two gases, H2 or H2O, deviates more from ideal behavior? Explain your answer.
H2O deviates more from ideal behavior because it is larger in size and has stronger IMFs than H2.
H2O has hydrogen bonding, while H2 has only weak London dispersion forces.
17. Consider the graph shown for the vapor pressure of diethyl
ether ((C2H5)2O), ethanol (C2H5OH), and water.
(a) For the three liquids:
(ii) Rank the three liquids in increasing strength of
inter-molecular forces.
Diethyl ether < ethanol < water
(iii) Explain how the rank in part (i) can be inferred
from the vapor pressure of the liquids shown in the
graph.
Substances with weaker IMFs have higher VP.
At a particular temperature (e.g. 20°C), diethyl
ether has the highest VP (460 torr) so it has the
weakest IMF, while water has the lowest VP (20
torr), so it has the strongest IMF.
(iv) Explain how the rank in part (i) can be justified
using the inter-molecular forces.
Diethyl ether has only dipole-dipole interactions, whereas ethanol and water have hydrogen
bonding. Because hydrogen bonding is stronger than dipole-dipole interactions, diethyl ether
has the weakest IMF among the three. Because water has the ability to form two hydrogen
bonding interactions, its hydrogen bonding is stronger than that of ethanol, which can only
form one hydrogen bond.
(v) One molecule of ethanol is shown below. Draw another molecule and show the attractive intermolecular forces between them.
(b) 20 mL liquid diethyl ether is placed in a closed container at 20°C. After awhile, some diethyl ether
remains.
(i) Describe what would be observed with the volume of the liquid diethyl ether over time.
The volume of the liquid diethyl ether would decrease as it evaporates. When the pressure
reaches the equilibrium vapor pressure, the volume of the liquid diethyl ether would stop
changing.
Pressure (torr)
(ii) Sketch the graph of the pressure of the container over time.
700
600
500
400
300
200
100
0
Time
(iii) Write the equilibrium constant expression, Kp, for the process observed, and find its value. Use
pressure units in atm.
(C2H5)2O(ℓ) (C2H5)2O(g)
1 atm
Kp = P(C2H5)2O = 450 torr
= 0.592
760 torr
(c) A sample of liquid ethanol is placed in a 5.0 L container at 30°C. After an hour, all of the ethanol has
been evaporated. What is the greatest volume of liquid ethanol that could have been placed in a container?
The density of liquid ethanol is 0.789 g/mL.
Because all of the ethanol has evaporated, the maximum pressure would be
1 atm
Pvap = 100 torr
= 0.132 atm.
760 torr
P·V
(0.132 atm)(5.0 L)
46.07 g C2H5OH
1 mL
n=
=
= 0.0265 mol C2H5OH
R·T
atm·L
1 mol C2H5OH 0.789 g C2H5OH
(0.08206
)(30 + 273 K)
mol·K
= 1.54 mL
South Pasadena • AP Chemistry
Name
10 ▪ States of Matter
Period
UNIT TEST
Date
BLUEPRINT
Part 1: Multiple Choice
Format: 15 questions, four answer choices: (A)-(D)
Expected time: 25 minutes
Allowed resources: Periodic Table, Equations and Constants. No calculators.
Q Lesson
1 8.1
2 8.1
3 8.1
4 8.1
5 8.2
6
7
8
9
8.2
8.2
8.2
8.2
10 8.2
11
12
13
14
8.2
8.2
8.2
8.3
15 8.3
Topic
Objective
Properties of Solids
Descriptions of
Solids
Describe the physical properties of various types of solids.
Describe how attractive and repulsive forces influence the hardness and
brittleness of ionic solids.
Describe an interstitial or substitutional allow using a particulate representation.
Explain how doping a family 14 element can create a semiconductor.
Types of Solid
Classify a solid based on its chemical formula and identify the inter-particle
force involved.
IMFs
Compare the strength of intermolecular forces between molecular compounds.
Biomolecules
Show how intermolecular forces are important in determining the structure of
biomolecules.
Phase Diagrams
Interpret a phase diagram.
Vapor Pressure
Explain how vapor pressure is related to the boiling point.
Properties of Liquids Use physical properties to compare the intermolecular forces of liquids.
Gas Laws
Relate how physical properties of a gas sample changes when pressure,
temperature, or volume changes.
Temperature
Describe the temperature as the average kinetic energy of a sample.
Molecular Speed
Compare the average speeds of various gases at a given temperature.
Partial Pressures
Determine the partial pressure of a gas in a mixture of gases.
Ideal Gas Law
Determine the properties of a gas sample using the ideal gas law.
Real Gases
Describe when and how an gas deviates from ideal behavior.
Colligative Properties Describe how the physical properties of a solution deviates from those of a pure
substance (i.e. boiling point, freezing point, vapor pressure).
Separation
Techniques
Explain how distillation and chromatography can be used to separate
components of a mixture based on physical properties.
Part 2: Free Response
Format:
o 1 long question (5-8 parts)
o 1 short question (2-4 parts)
Expected time: 30 minutes
Allowed resources: Periodic Table, Equations and Constants, and scientific calculators.
Topics: Any