12
CHAPTER
SOLUTIONS MANUAL
States of Matter
Section 12.1 Gases
2. Calculate What is your actual diving depth
if your depth gauge reads 18 m, but you are at
an altitude of 1800 m and your gauge does not
compensate for altitude?
pages 402–410
Practice Problems
page 405
1. Calculate the ratio of effusion rates for nitrogen
3. Infer Dive tables are used to determine how
(N2) and neon (Ne).
RateN/RateNe 0.849
molar mass
Rate
20.18
_
__ √_ 0.849
√ molar mass Rate
28.02
N
Ne
Ne
N
2. Calculate the ratio of diffusion rates for carbon
monoxide and carbon dioxide.
1.25
√
molar
mass
Rate
_
__
CO
RateCO2
CO2
molar massCO
44.01
_
1.25
√
28.01
3. Challenge What is the rate of effusion for a
gas that has a molar mass twice that of a gas
that effuses at a rate of 3.6 mol/min?
x
2
3.6 mol/min
Ratex 2.5 mol/min
long it is safe for a diver to stay under water at
a specific depth. Why is it important to know
the correct depth of the dive?
The amount of time that it is safe to stay under
water is directly related to the diving depth. If
you do not know your actual diving depth, you
cannot determine how long it is safe to stay at a
particular diving depth.
Practice Problems
page 409
4. What is the partial pressure of hydrogen gas in
a mixture of hydrogen and helium if the total
pressure is 600 mm Hg and the partial pressure
of helium is 439 mm Hg?
161 mm Hg
600 mmHg 439 mmHg 161 mmHg
5. Find the total pressure for a mixture that
Data Analysis Lab
page 408
1. Compare Use the data in the table to make
a graph of atmospheric pressure versus altitude.
Check student graphs
Atmospheric Pressure
v. Altitude
1.0
Atmospheric
Pressure (atm)
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2.5 mol/min
Rate
1
__
√_
18 m 2 m 20 m
0.9
contains four gases with partial pressures of
5.00 kPa, 4.56 kPa, 3.02 kPa, and 1.20 kPa.
5.00 kPa 4.56 kPa 3.02 kPa 1.20 kPa 13.78 kPa
6. Find the partial pressure of carbon dioxide in a
gas mixture with a total pressure of 30.4 kPa if
the partial pressures of the other two gases in
the mixture are 16.5 kPa and 3.7 kPa.
30.4 kPa 16.5 kPa 3.7 kPa 10.2 kPa
0.8
0.7
0.6
0.5
0.4
0
600
1200
1800
2400
3000
Altitude (m)
Solutions Manual
Chemistry: Matter and Change • Chapter 12
237
12
7. Challenge Air is a mixture of gases. By
percentage, it is roughly 78 percent nitrogen,
21 percent oxygen, and 1 percent argon. (There
are trace amounts of many other gases in air.) If
the atmospheric pressure is 760 mm Hg, what
are the partial pressures of nitrogen, oxygen,
and argon in the atmosphere?
760 mm Hg 0.78 N2 590 mm Hg;
760 mm Hg 0.21 O2 160 mm Hg;
760 mm Hg 0.01 Ar 8 mm Hg
Section 12.1 Assessment
page 410
8. Explain Use the kinetic theory to explain the
behavior of gases.
Gases consist of small particles in random motion
which experience elastic collisions.
9. Describe how the mass of a gas particle affects
its rate of effusion and diffusion.
The rate of effusion and diffusion decreases as
mass increases.
10. Explain how gas pressure is measured.
Atmospheric pressure is measured using a
barometer. The gas pressure in a closed container
is measured using a manometer.
11. Explain why the container of water must be
inverted when a gas is collected by displacement of water.
If the container is not inverted, the gas, which is
less dense than water, will rise through the water
and escape from the opening of the container.
12. Calculate Suppose two gases in a container
have a total pressure of 1.20 atm. What is the
pressure of gas B if the partial pressure of gas A
is 0.75 atm?
1.20 atm 0.75 atm 0.45 atm
13. Infer whether or not temperature has any effect
on the diffusion rate of a gas. Explain your
answer.
As temperature increases the velocity of the
particles increase and the particles will
diffuse faster.
238
Chemistry: Matter and Change • Chapter 12
SOLUTIONS MANUAL
Section 12.2 Forces of Attraction
pages 411–414
Section 12.2 Assessment
page 414
14. Explain what determines a substance’s state at
a given temperature.
The intermolecular forces between the particles
determine the state of a substance. In a solid, the
intermolecular forces are very strong and hold the
particles together. In a liquid, the intermolecular
forces are weaker and in a gas, the particles no
longer experience intermolecular forces.
15. Compare and contrast intermolecular forces
and describe intramolecular forces.
Intermolecular forces occur between particles.
Intramolecular forces hold particles together.
16. Evaluate Which of the molecules listed below
can form hydrogen bonds? For which of the
molecules would dispersion forces be the only
intermolecular force? Give reasons for
your answers
a. H2
b. H2S
c. HCl
d. HF
hydrogen bonds: b, d; only dispersion forces:
a; b and d are polar molecules with a highly
electronegative atom bonded to hydrogen
a is nonpolar
17. Intepret Data In a methane molecule (CH4),
there are four single covalent bonds. In an
octane molecule (C8H18), there are 25 single
covalent bonds. How does the number of bonds
affect the dispersion forces in samples of
methane and octane? Which compound is a gas
at room temperature? Which is a liquid?
More bonds mean more electrons to form
temporary dipoles, which means greater
dispersion forces. Methane is a gas; octane is
a liquid.
Solutions Manual
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
CHAPTER
CHAPTER
12
Section 12.3 Liquids and Solids
pages 415–424
Section 12.3 Assessment
page 424
18. Contrast the arrangement of particles in solids
and liquids.
The particles are closer together in solids than
in liquids because of intermolecular attractions.
Most solids have a regular repeating particle
arrangement while liquids have none.
19. Describe the factors that affect viscosity.
Viscosity of a liquid is determined by the type of
intermolecular forces in the liquid, the size and
shape of the particles, and the temperature.
SOLUTIONS MANUAL
25. Predict which solid is more likely to be
amorphous—one formed by allowing a molten
material to cool slowly to room temperature
or one formed by quickly cooling the same
material in an ice bath.
The one cooled quickly in an ice bath because
amorphous solids often form when molten
material cools too quickly for crystals to form.
26. Design an experiment to compare the rela-
tive abilities of water and isopropyl alcohol to
support skipping stones. Include a prediction
about which liquid will be better along with a
brief explanation of your prediction.
Make sure students use correct scientific
procedures in their experimental designs.
20. Explain why soap and water are used to clean
clothing instead of water alone.
Section 12.4 Phase Changes
Soaps and detergents decrease the surface
tension of water by breaking the hydrogen
bonds, which allows the dirt to be carried away
by the water.
pages 425–430
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
21. Compare a unit cell and a crystal lattice.
Unit cells are the building blocks of the crystal
lattice.
22. Describe the difference between a molecular
solid and a covalent network solid.
A molecular solid is formed from molecules held
together by intermolecular forces that are weaker
than covalent bonds; covalent network solids are
formed from molecules held together by covalent
bonds.
23. Explain why water forms a meniscus when it
is in a graduated cylinder.
Because the adhesive forces between water
molecules and the silicon dioxide in glass are
greater than the cohesive forces between water
molecules, the water rises along the inner walls
of the cylinder.
24. Infer why the surface of mercury in a
thermometer is convex; that is, the surface is
higher at the center.
Section 12.4 Assessment
page 430
27. Explain how the addition or removal of energy
can cause a phase change.
The addition of energy increases the kinetic
energy of the particles, which reduces the
intermolecular forces between the particles. As
energy is removed, the kinetic energy of the
particles decreases and intermolecular forces
increase.
28. Explain the difference between the processes
of melting and freezing.
Freezing occurs when a liquid becomes a solid
and energy is released. Melting requires an input
of energy to convert a solid to a liquid.
29. Compare deposition and sublimation.
A substance undergoes deposition when it goes
from the vapor phase to the solid phase without
going through the liquid phase. A substance
undergoes sublimation when it goes from the
solid phase directly to the vapor phase without
going through the liquid phase. Both occur at the
same temperature for a given substance.
The cohesion between mercury atoms is stronger
than the adhesion between mercury and glass.
Solutions Manual
Chemistry: Matter and Change • Chapter 12
239
12
SOLUTIONS MANUAL
30. Compare and contrast sublimation and
evaporation.
In both processes, the substances become a vapor.
During sublimation, the substance goes from the
solid phase directly to the vapor phase. During
evaporation, particles in a liquid gain enough
energy to enter the vapor phase. Both occur at the
same temperature for a given substance.
31. Describe the information that a phase diagram
supplies.
pages 434–437
Section 12.1
one in which no kinetic energy is lost
32. Explain what the triple point and the critical
35. How does the kinetic energy of particles vary as
point on a phase diagram represents.
a function of temperature?
Triple point: the temperature at which the three
phases of a substance can coexist; critical point:
the pressure and temperature above which a
substance cannot exist as a liquid
It is directly proportional to their temperature.
36. Use the kinetic-molecular theory to explain the
compression and expansion of gases.
33. Determine the phase of water at 75.00°C and
3.00 atm using Figure 12.29.
Phase Diagram for H2O
Critical point
217.75
Pressure (atm)
Chapter 12 Assessment
Mastering Concepts
34. What is an elastic collision?
The combinations of temperature and pressure
under which a given substance exists as a solid,
liquid, and/or gas.
B
Because of the space between gas particles, gases
are easily compressed when pushed into a smaller
volume. When the pressure is removed, their
random motion enables gases to expand.
37. List the three basic assumptions of the kinetic-
molecular theory.
1. Matter is composed of small particles.
Liquid
Normal
freezing
point
2. The particles are in constant motion and
undergo elastic collisions.
1.00
Solid
Normal
boiling
point
3. The particles have kinetic energy and the
average kinetic energy of the particles is
temperature.
A
Vapor
Triple point
0.00
100.00
38. Describe the common properties of gases.
373.99
Temperature (°C)
liquid
Everyday Chemistry
page 431
Writing in Chemistry
Research to find out more about chocolate and write
a short report. For more information about chocolate,
visit glencoe.com.
240
The reports might contain a variety of
information, such as where the beans are grown,
how they are processed, or how the final product
is distributed and sold.
Chemistry: Matter and Change • Chapter 12
Gases have low density, can be compressed, will
expand to fill all available space, and can undergo
diffusion and effusion.
39. Compare diffusion and effusion. Explain the
relationship between the rates of these processes
and the molar mass of a gas.
Both involve the movement of gas particles.
Diffusion is the movement of one substance
through another; effusion is when a substance
under pressure escapes through a tiny opening.
Effusion and diffusion rates are inversely related
to molecular mass of a gas.
Solutions Manual
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CHAPTER
12
CHAPTER
SOLUTIONS MANUAL
40. In Figure 12.31, what happens to the density of
44. Calculate the molar mass of a gas that diffuses
gas particles in the cylinder as the piston moves
from Position A to Position B?
three times faster than oxygen under similar
conditions.
a
Rate
molar mass
_
__
b
O2
Ratex
√
x
molar massO2
MM
_1 √
_
3.56 g/mol
x
3
32.00
3.56 g/mol
45. What is the partial pressure of water vapor in an
Density decreases because the gas particles
occupy more volume per unit mass.
41. Baking at Different Elevations Explain
why the baking instructions on a box of cake
mix are different for high and low elevations.
Would you expect to have a longer or shorter
cooking time at a high elevation?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Because of the variation in air pressure with
elevation; At high elevations, reduced air pressure
results in a lower boiling point for water and
cooking time is longer.
Mastering Problems
42. What is the molar mass of a gas that takes three
times longer to effuse than helium?
Ratex
√
1.00 atm 0.79 atm 0.20 atm 0.0044 atm
0.01 atm
46. What is the total gas pressure in a sealed flask
that contains oxygen at a partial pressure of
0.41 atm and water vapor at a partial pressure
of 0.58 atm?
0.41 atm 0.58 atm 0.99 atm
47. Mountain Climbing The pressure atop the
world’s highest mountain, Mount Everest, is
usually about 33.6 kPa. Convert the pressure to
atmospheres. How does the pressure compare
with the pressure at sea level?
33.6 kPa (1 atm/101.325 kPa) 0.332 atm
Rate
molar mass
_
__
He
air sample when the total pressure is 1.00 atm,
the partial pressure of nitrogen is 0.79 atm,
the partial pressure of oxygen is 0.20 atm, and
the partial pressure of all other gases in air is
0.0044 atm?
x
0.332 atm; It is about one-third of the 1-atm
pressure at sea level.
molar massHe
MM
_3 √
__
36.0 g/mol
x
1
48. High Altitude The atmospheric pressure in
4.00 g/mol
Denver, Colorado, is usually about 84.0 kPa.
What is this pressure in atm and torr units?
36.0 g/mol
43. What is the ratio of effusion rates of krypton
and neon at the same temperature and pressure?
_ __ √_
√ molar mass
Rate
RateKr
molar massNe
Ne
Kr
RateKr/RateNe 0.4931
20.18
0.4931
83.80
84.0 kPa (1 atm/101.325 kPa) 0.829 atm
84.0 kPa (760 torr/101.325 kPa) 6.30 102 torr
84.0 kPa 0.829 atm and 6.30 102 torr
49. At an ocean depth of 76.2 m, the pressure is
about 8.4 atm. Convert the pressure to mm Hg
and kPa units.
8.4 atm (760 mmHg/1 atm) 6400 mm Hg
8.4 atm (101.325 kPa/1 atm) 850 kPa
8.4 atm 8.5 102 kPa and 6.4 103 mm Hg
Solutions Manual
Chemistry: Matter and Change • Chapter 12
241
CHAPTER
12
SOLUTIONS MANUAL
50. Figure 12.32 represents an experimental set-up
in which the left bulb is filled with chlorine gas
and the right bulb is filled with nitrogen gas.
Describe what happens when the stopcock is
opened. Assume the temperature of the system
is held constant during the experiment.
The gases will diffuse until both bulbs are filled
with the same gas mixtures.
53. Explain why hydrogen bonds are stronger than
most dipole-dipole forces.
A hydrogen bond involves a large difference in
electronegativity between the hydrogen atom
and the atom it is attached to (O, N, or F), making
the bond extremely polar.
54. Compare intramolecular and intermolecular
forces.
Intramolecular forces hold atoms together in
a molecule while intermolecular forces hold
different molecules together.
55. Hypothesize why long, nonpolar molecules would
Chlorine gas
Nitrogen gas
After one hour
interact more strongly with one another than spherical nonpolar molecules of similar composition.
Because long molecules have greater surface
areas, more intermolecular forces can exist.
Mastering Problems
Nitrogen and
chlorine gas
Nitrogen and
chlorine gas
Section 12.2
Mastering Concepts
51. Explain the difference between a temporary
dipole and a permanent dipole.
A temporary dipole forms when one molecule is
close to another molecule and the electrons repel
each other creating a greater electron density in
one part of the molecule. Permanent dipoles are
found in polar molecules in which some regions
of the molecule are always partially positive and
partially negative.
52. Why are dispersion forces weaker than dipole-
electronegativity to label the ends of the polar
molecules listed as partially positive or partially
negative.
a. HF
HF
b. HBr
NO
c. NO
HBr
b. CO
CO
57. Draw the structure of the dipole-dipole interaction
between two molecules of carbon monoxide.
dipole forces?
Dispersion forces are between temporary dipoles.
Dipole-dipole forces are between permanent
dipoles.
See Figure 13.8. The drawing should show two
CO molecules, with the C partially positive and
the O partially negative. The C of each molecule
should be bonded to the O of the other.
242
Chemistry: Matter and Change • Chapter 12
Solutions Manual
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
56. Polar Molecules Use relative differences in
CHAPTER
12
SOLUTIONS MANUAL
58. Decide which of the substances listed can form
hydrogen bonds.
a. H2O
b. H2O2
c. HF
d. NH3
capillary action.
All of the substances can form hydrogen bonds.
59. Decide which one of the molecules listed below
can form intermolecular hydrogen bonds,
and then draw it, showing several molecules
attached together by hydrogen bonds.
a. NaCl
b. MgCl2
c. H2O2
d. CO2
c H2O2 can form intermolecular hydrogen bonds.
—
H
—
—
O—O H
Hydrogen
bond
—
—
H O—O H
—
H O—O
H
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
63. Explain how two different forces play a role in
Section 12.3
Mastering Concepts
60. What is surface tension, and what conditions
must exist for it to occur?
The energy needed to increase the surface area of
a liquid by a given amount; strong intermolecular
forces exist between the liquid particles
Capillary action results from the opposing forces
of adhesion and cohesion. Adhesive forces
between water molecules and molecules in the
glass of a capillary tube are stronger than the
cohesive forces holding water molecules together,
so water moves up the walls of the capillary tube.
64. Use the drawings in Figure 12.33 to compare
the cubic, monoclinic, and hexagonal crystal
systems.
α
α
β
a γ
β
α
c
b
β
γ
a
c
b
a=b≠c
α = β = 90°, γ = 120°
a≠b≠c
α = γ = 90° ≠ β
Hexagonal
Monoclinic
c
γ a
b
a=b=c
α = β = γ = 90°
Cubic
In the cubic crystal system, all of the sides are
an equal length and the angles are all 90°. In the
monoclinic crystal system, a, b, and c are unequal
in length and and are 90° angles, but is not.
In the hexagonal crystal system, a and b are equal
in length, but c is not. The angles and are
equal to 90°, but is equal to 120°.
65. What is the difference between a network solid
and an ionic solid?
Network solid is held together by covalent bonds;
ionic solid by electrostatic attraction.
66. Explain why most metals bend when struck but
most ionic solids shatter.
61. Explain why the surface of water in a graduated
cylinder is curved.
Adhesion between water and glass is greater
than cohesion between water molecules.
The sea of electrons that holds metal ions
together can easily move to accommodate
outside forces; in ionic solids a strong force
can separate the solid along the plane bonding
groups of atoms together.
62. Which liquid is more viscous at room tempera-
ture, water or molasses? Explain.
Molasses; stronger intermolecular forces keep
molasses from flowing.
Solutions Manual
67. List the types of crystalline solids that are
usually good conductors of heat and electricity.
metallic solids; ionic solids when molten or
dissolved in an aqueous solution
Chemistry: Matter and Change • Chapter 12
243
CHAPTER
12
68. How does the strength of a liquid’s intermo-
lecular forces affect its viscosity?
Stronger intermolecular forces result in higher
viscosity because the forces hold the particles
together too tightly for them to flow easily.
69. Explain why water has a higher surface tension
than benzene, whose molecules are nonpolar.
Surface tension increases with strength of
intermolecular forces. Water molecules are held
together by strong hydrogen bonds, resulting
in higher surface tension; the weaker dispersion
forces between benzene molecules result in lower
surface tension.
70. Compare the number of particles in one unit
cell for each of the following types of unit cells.
a. simple cubic
8
b. body-centered cubic
SOLUTIONS MANUAL
Mastering Problems
74. Given edge lengths and face angles, predict the
shape of each of the following crystals.
a. a 3nm, b 3 nm, c 3nm and 90°,
° 90 and 90°
cubic
b. a 4nm, b 3 nm, c 5nm and 90°,
° 100 and 90°
monoclinic
c. a 3nm, b 3 nm, c 5nm and 90°,
° 90 and 90°
tetragonal
d. a 3nm, b 3 nm, c 5nm and 90°,
° 90 and 120°
hexagonal
Section 12.4
9
amorphous – one formed by cooling a molten
material over 4 hours at room temperature
or one formed by cooling a molten material
quickly in an ice bath.
The one cooled quickly in an ice bath because
amorphous solids often form when molten
material cools too quickly for crystals to form.
72. Conductivity Predict which solid will conduct
electricity better—sugar or salt.
Salt, because it contains ions while sugar is a
molecular solid without any ions.
73. Explain why ice floats in water but solid
benzene sinks in liquid benzene. Which
behavior is more “normal”?
Surface tension increases with strength of
intermolecular forces. Water molecules are held
together by strong hydrogen bonds, resulting
in higher surface tension; the weaker dispersion
forces between benzene molecules result in lower
surface tension. Benzene is more “normal”.
Mastering Concepts
75. How does sublimation differ from deposition?
Sublimation occurs when a solid is converted to a
gas; deposition occurs when a gas is converted to
a solid.
76. Compare boiling and evaporation.
Evaporation: conversion of a liquid to a gas at the
liquid’s surface; boiling: when vapor pressure is
equal to external atmospheric pressure; it occurs
at and below the surface where bubbles form.
77. Define the term melting point.
the temperature at which the crystal lattice of a
solid disintegrates and it becomes a liquid
78. Explain the relationships among vapor pressure,
atmospheric pressure, and boiling point.
Boiling point is the temperature at which vapor
pressure exerted by liquid molecules escaping
from the surface of a sample equals the
atmospheric pressure on the surface of the liquid.
79. Explain why dew forms on cool mornings.
When water vapor in the air comes in contact
with a cool object such as a windshield, it
condenses on the object.
244
Chemistry: Matter and Change • Chapter 12
Solutions Manual
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71. Predict which solid is more likely to be
12
CHAPTER
SOLUTIONS MANUAL
80. Why does a pile of snow slowly shrink even on
days when the temperature never rises above
the freezing point of water?
Some of the snow sublimes.
85. Use the kinetic-molecular theory to explain why
gases are easier to compress than liquids or solids.
Because particles in gases are farther apart than
particles in liquids or solids, there is more space
for the particles to be compressed.
81. Phase Diagrams Copy and label the solid,
liquid, and gas phases, triple point, and critical
point on Figure 12.34.
Phase Diagram
Pressure (atm)
16
Solid
Critical point
is not shown
Liquid
8
Gas
0
-100
Triple point
-80
-60
-40
-20
0
+20
+40
Temperature (°C)
82. Why does it take more energy to boil 10 g of
liquid water than to melt an equivalent mass
of ice?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
of mercury is 13.5 g/mL; water at the same
temperature and pressure has a density of
1.00 g/mL. Explain this difference in terms of
intermolecular forces and the kinetic-molecular
theory.
Metallic bonds holding mercury atoms together
are stronger than hydrogen bonds holding water
molecules together, so the mercury atoms are
more closely packed, resulting in greater mass per
unit volume.
12
4
86. At 25ºC and a pressure of 760 mm Hg, the density
Melting does not require as much energy because
the particles in a solid do not have to move far
apart or gain much movement to form a liquid.
Gas particles are much further apart and move
much more rapidly than liquid particles.
87. If two identical containers each hold the same
gas at the same temperature but the pressure
inside one container is exactly twice that of the
other container, what must be true about the
amount of gas inside each container?
The container with twice the pressure has twice
the number of particles.
88. List three types of intermolecular forces.
hydrogen bonding, dispersion forces,
dipole-dipole forces
89. When solid sugar crystals are dissolved in a
Mixed Review
83. Use the kinetic-molecular theory to explain why
both gases and liquids are fluids.
Because the particles in gases and liquids are held
together by fewer attractive forces than in solids,
allowing them to flow
84. Use intermolecular forces to explain why
oxygen is a gas at room temperature and water
is a liquid.
Oxygen molecules are nonpolar and held together
by dispersion forces, making them easy to separate.
Water molecules are held together by stronger
hydrogen bonds, making them harder to separate.
As a result, water has a higher boiling point.
Solutions Manual
glass of water, they form a clear homogeneous
solution in which the crystals are not visible. If
the beaker is left out at room temperature for
a few days, the crystals reappear in the bottom
and on the sides of the glass. Is this an example
of freezing?
No. The only phase change that occurred is liquid
water evaporating to form water vapor. The
sugar was always in the solid phase, even when
not visible. The crystals became large enough to
see with the unaided eye over time.
Chemistry: Matter and Change • Chapter 12
245
CHAPTER
12
SOLUTIONS MANUAL
Think Critically
92. Compare and Contrast An air compressor
90. Interpret Graphs Examine Figure 12.35,
which plots vapor pressure versus temperature
for water and ethanol.
Vapor pressure (torr)
Vapor Pressure v. Temperature
800
760
600
400
Ethanol
Water
200
0
-40
-20
0
20
40
60
80
100
Temperature (°C)
a. What is the boiling point of water at 1 atm?
uses energy to squeeze air particles together.
When the air is released, it expands, allowing
the energy to be used for purposes such as
gently cleaning surfaces without using a more
abrasive liquid or solid. Hydraulic systems
essentially work the same way, but they involve
compression of liquids rather than air. What do
you think are some advantages and disadvantages of these two types of technology?
Air compressors produce rapid outputs of a large
amount of energy because gases can be greatly
compressed. Hydraulic systems involve liquid
water, which cannot be compressed as much,
and are more useful for a slow, steady output of
energy.
93. Graph Use Table 12.6 to construct a phase
diagram for ammonia.
100°C
1 atm?
Selected
Points
Pressure
(atm)
Temperature
(˚C)
78.5°C
Triple point
0.060
–77.7
c. Estimate the temperature at which water will
boil when the atmospheric pressure is 0.80
atm.
94°C
Critical point
112
132.2
Normal boiling
point
1.0
–33.5
Normal
freezing point
1.0
–77.7
91. Hypothesize What type of crystalline solid
molecular solid
b. a material that can be drawn into long, thin
wires
metallic solid
c. a material that conducts electricity when
molten
Phase Diagram for Ammonia
120
Critical point
80
Solid
100
Pressure (atm)
do you predict would best suit the following
needs?
a. a material that can be melted and reformed
at a low temperature
Liquid
60
40
0
–20
Gas
Freezing
point
20
Triple point Boiling point
0
–100
–50
0
50
100
100
150
Temperature (°C)
ionic solid
d. an extremely hard material that is
nonconductive
covalent network solid
246
Chemistry: Matter and Change • Chapter 12
Solutions Manual
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Phase Diagrams for Ammonia
b. What is the boiling point of ethanol at
CHAPTER
12
94. Apply A solid being heated stays at a constant
temperature until it is completely melted. What
happens to the heat energy put into the system
during that time?
The energy is used to break the intermolecular
forces holding the particles of the solid together.
SOLUTIONS MANUAL
99. Evaluate Supercrital carbon dioxide is a
liquid form of CO2 used in the food industry to
decaffeinate tea, coffee, and colas, as well as in
the pharmaceutical industry to form polymer
microparticles used in drug delivery systems. Use
Figure 12.36 to determine what conditions must
be used to form supercritical carbon dioxide.
95. Communicate Which process—effusion or
diffusion; gas particles in the perfume are mixing
with air particles
96. Infer A laboratory demonstration involves
pouring bromine vapors, which are a deep red
color, into a flask of air and then tightly sealing
the top of the flask. The bromine is observed
to first sink to the bottom of the beaker. After
several hours have passed, the red color is
distributed equally throughout the flask.
a. Is bromine gas more or less dense than air?
more dense
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
b. Would liquid bromine diffuse more or less
quickly than gaseous bromine after you pour
it into another liquid?
less quickly
97. Analyze Use your knowledge of intermolecular
forces to predict whether ammonia (NH3) or
methane (CH4) will be more soluble in water.
Ammonia will be more soluble in water than
methane becuase ammonia and water can form
relatively strong intermolecular attractions
(hydrogen bonds) between them. Methane
(a nonpolar molecule) and water will form only
intermolecular dispersive forces which are weaker
than hydrogen bonds.
98. Evaluate List three PHASE changes that
require energy and three that release energy.
requires energy—melting, sublimation,
vaporization; releases energy—freezing,
deposition, condensation
Phase Diagram for CO2
Pressure (bar)
diffusion—is responsible for your being able
to smell perfume from an open bottle that is
located across the room from you? Explain.
Supercritical
fluid
73
5
-56.6
31.1
Temperature (ºC)
a pressure above 73 bars and a temperature
above 31.1°C
Challenge Problem
100. You have a solution containing 135.2 g of
dissolved KBr in 2.3 L of water.
What volume of this solution, in mL, would
you use to make 1.5 L of a 0.1 mol/L KBr
solution?
Molar mass of KBr 0 119.00 g 1 mol
135.2 g KBr
1 mol KBr
__
__ 0.49 mol/L KBr/water
2.3L water
119.00 gKBr
0.1 mol
0.49 mol
_
V
_ 31.5 L
stock
L
L
V stock 0.3 L 300 mL
Cumulative Review
101. Identify each of the following as an element,
a compound, a homogeneous mixture, or
heterogeneous mixture. (Chapter 3)
a. air
homogeneous mixture
b. blood
heterogeneous mixture
c. antimony
element
Solutions Manual
Chemistry: Matter and Change • Chapter 12
247
CHAPTER
12
d. ammonia
SOLUTIONS MANUAL
Additional Assessment
compound
e. mustard
heterogeneous mixture
f. water
compound
102. You are given two clear, colorless aqueous
solutions. You are told that one solution
contains an ionic compound and one contains
a covalent compound. How could you
determine which is an ionic solution and
which is a covalent solutions? (Chapter 9)
They could be tested for conductivity. The ionic
compound in solution should conduct electricity;
the covalent compound should not.
Writing in Chemistry
106. Musk is the basic ingredient of many
perfumes, soaps, shampoos, and even foods
like chocolates, licorice, and hard candies.
Both synthetic and natural musk molecules
have high molar masses compared to other
perfume ingredients, and as a result, have
a slower rate of diffusion assuring a slow,
sustained release of fragrance. Write a report
on the chemistry of perfume ingredients,
emphasizing the importance of diffusion rate
as a property of perfume.
Student reports should point out that a
slow diffusion rate results in a longer lasting
fragrance.
107. Birthstones Find out what your birthstone is
study matter and phase changes? (Chapter 1)
a. biochemistry
b. organic chemistry
c. physical chemistry
d. polymer chemistry
c
Check student reports for accuracy.
108. Propane gas is a commonly used heating
104. What type of reaction is the following?
(Chapter 9)
K2CO3(aq) BaCl2(aq) 0 2KCl(aq) BaCO3(s)
a. combustion
b. double-replacement
c. single-replacment
d. synthesis
b
fuel for gas grills and homes. However, it
is not packaged as a gas. It is liquefied and
referred to as liquid propane or “LP gas.”
Make a poster explaining the advantages and
disadvantages of storing and transporting
propane as a liquid rather than a gas.
A liquid requires a smaller container than a gas
and the container can hold more fuel as a liquid
rather than a solid.
109. Other States of Matter Research and
and accepted periodic table? (Chapter 6)
a. Dimitri Mendeleev
b. Henry Moseley
c. John Newlands
d. Lothar Meyer
prepare an oral report about one of the
following topics: plasma, superfluids, fermionic condensate, or Bose-Einstein condensate.
Share your report with your classmates and
prepare a visual aid that can be used to explain
your topic.
a
Check student reports.
105. Which chemist produced the first widely used
248
and write a brief report about the chemistry of
that gem. Find out its chemical composition,
which category its unit cell is in, how hard
and durable it is, and its approximate cost at
present.
Chemistry: Matter and Change • Chapter 12
Solutions Manual
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
103. Which branch of chemistry would most likely
CHAPTER
12
SOLUTIONS MANUAL
Document-Based Questions
110. Why does solid iodine sublime readily? Use
your knowledge of intermolecular forces to
explain.
The dispersion forces that hold iodine molecules
together in its solid crystal are relatively weak
so when those bonds break, the atoms can move
apart directly from the solid to the gas state.
111. Why is liquid iodine not usually visible if
crystals are heated in the open air?
Iodine melts at 112.9°C, boils at 183.0°C, and its
vapor pressure is 100 mm Hg at 116.5°C. When
being heated rapidly or in a closed vessel solid
iodine will melt. A vapor pressure of about
100 mm Hg must be attained to allow liquid
iodine to form and prevent sublimation. In
containers open to the air, the crystals will
usually sublime completely before melting.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
112. Why is it necessary to use a sealed ampoule in
2. Which is NOT an assumption of the
kinetic-molecular theory?
a. Collisions between gas particles are elastic.
b. All the gas particles in a sample have the
same velocity.
c. A gas particle is not significantly attracted
or repelled by other gas particles.
d. All gases at a given temperature have the
same average kinetic energy.
b
3. A sealed flask contains neon, argon, and
krypton gas. If the total pressure in the flask is
3.782 atm, the partial pressure of Ne is 0.435
atm, and the partial pressure of Kr is 1.613 atm,
what is the partial pressure of Ar?
a. 2.048 atm
b. 1.734 atm
c. 1556 atm
d. 1318 atm
this investigation?
b
If the ampoule were not sealed, the iodine vapor
would escape into the room.
3.782 0.435 1.613 atm 1.734 atm
113. Infer why the iodine solidifies when the tube is
tilted.
The iodine cools quickly as it is tilted.
Use the figure below to answer Question 4.
4. Hydrogen and nitrogen react as shown to form
ammonia (NH3). What will be true of this
reaction?
Standardized Test Practice
+
pages 438–439
1. What is the ratio of effusion rates for nitric
3 nitrogen molecules
(6 nitrogen atoms)
3 hydrogen molecules
(6 hydrogen atoms)
oxide (NO) and nitrogen tetroxide
(N2O4)?
a. 0.326
b. 0.571
c. 1.751
d. 3.066
a. Three ammonia molecules will be formed,
c
c. Six ammonia molecules will be formed,
molar mass
Rate
92.01
_
__ √_
√ molar mass 30.01
NO
Rate N204
1.751
Solutions Manual
with zero molecules left over.
b. Two ammonia molecules will be formed,
with two hydrogen molecules left over.
with zero molecules left over.
N204
d. Two ammonia molecules will be formed,
NO
with two nitrogen molecules left over.
d
Chemistry: Matter and Change • Chapter 12
249
CHAPTER
12
SOLUTIONS MANUAL
5. Which does not affect the viscosity of a liquid?
a.
b.
c.
d.
8. In what form or forms does carbon exist at
6000 K and 105 atm?
a. diamond only
b. liquid carbon only
c. diamond and liquid carbon
d. liquid carbon and graphite
intermolecular attractive forces
size and shape of molecules
temperature of the liquid
capillary action
d
b
Use the graph below to answer Questions 6–8.
Use the table below to answer Questions 9–10.
Phase Diagram for Carbon
Diamond
105
Pressure (atm)
Liquid
104
Bond
Strength
(kJ/mol)
Length (pm)
H—H
435
74
Br—Br
192
228
C—C
347
154
C—H
393
104
C—N
305
147
103
102
Graphite
101
Vapor
100
0
2000
4000
C—O
356
143
CI—CI
243
199
I—I
151
267
S—S
259
208
6000
Temperature (ºC)
9. Create a graph to show how bond length varies
with bond strength. Place bond strength on the
x-axis.
6. Under what conditions is diamond most likely
Relationship between bond length and strength
300
250
Bond length, pm
to form?
a. temperatures > 5000 K and pressures
< 100 atm
b. temperatures > 6000 K and pressures
> 25 atm
c. temperatures < 3500 K and pressures
> 105 atm
d. temperatures < 4500 K and pressures
< 10 atm
200
150
100
50
0
0
50
100
150
200
250
300
350
400
450
500
Bond strength, kJ/mol
c
7. Find the point on the graph at which carbon
exists in three phases: solid graphite, solid
diamond, and liquid carbon. What are the
temperature and pressure at that point?
a. 4700 K and 106 atm
b. 3000 K and 103 atm
c. 5100 K and 105 atm
d. 3500 K and 80 atm
10. Summarize the relationship between bond
strength and bond length.
As the bond strength increases, the bond length
decreases.
d
250
Chemistry: Matter and Change • Chapter 12
Solutions Manual
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
106
Properties of Single Bonds
CHAPTER
12
SOLUTIONS MANUAL
Use the table below to answer Question 11.
Geometry of AlCl3 and PCl3
Compound
AlCl3
PCl3
Molecular
Shape
13. The solid phase of a compound has a definite
shape and volume because its particles
a. are not in constant motion.
b. are always more tightly packed in the liquid
phase.
c. can vibrate only around fixed points.
d. are held together by strong intramolecular
forces.
e. have no intermolecular forces.
c
11. What are the names of the shapes of the mole-
Use the table below to answer Questions 14 and 15.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
cules for each compound? Explain how the
atomic arrangements in each compound result
in their different shapes despite their similar
formulas.
AlCl3 has a trigonal planar shape, while PCl3 has
trigonal pyramidal shape. The difference in their
shapes is due to the number of unpaired electron
pairs. Because aluminum has three valence
electrons, when it bonds to chlorine, all of those
electrons are used in bonding and no unpaired
electrons are left, therefore giving it a planar
shape. PCl3 has a pyramidal shape because its
five valence electrons are not all used in bonding
to three chlorine atoms, leaving one pair of
electrons, which repel the bonding electrons to
make a three-dimensional shape.
12. Potassium chromate and lead(II) acetate are
both dissolved in a beaker of water, where they
react to form solid lead(II) chromate. What is
the balanced net ionic equation describing this
reaction?
a. Pb2(aq) C2H3O2−(aq) 0 Pb(C2H3O2)2(s)
b. Pb2(aq) 2CrO4− (aq) 0 Pb(CrO4)2(s)
c. Pb2(aq) CrO42− (aq) 0 PbCrO4(s)
d. Pb(aq) C2H3O2−(aq) 0 PbC2H3O2(s)
e. Pb2(aq) CrO4− (aq) 0 PbCrO5(s)
c
Solutions Manual
Properties of Sulfuric Acid
Formula
H2SO4
Molar mass
98.08 g/mol
Density
1.834 g/mL
14. What is the mass of 75.0 mL of sulfuric acid?
a.
b.
c.
d.
e.
40.9 g
138 g
98.08 g
180 g
198.4 g
b
75.0 mL (1.834 g/1 mL) 138 g
15. How many atoms of oxygen are present in
2.4 mol of sulfuric acid?
a. 940 atoms
b. 230 atoms
c. 1.5 10 24 atoms
d. 5.8 10 24 atoms
e. 6.02 10 23 atoms
d
2.4 mol H2SO4 6.02 10 molecules
___
23
1 mol H2SO4
4 atoms O 5.8 1024 atoms
__
1 molecule
Chemistry: Matter and Change • Chapter 12
251