AP Chemistry Practice Test #7 (Unit 8)
Chapters 10 and 11
1. Which one of the following decreases as the strength of the attractive intermolecular forces
increases?
a.
b.
c.
d.
e.
The heat of vaporization.
The normal boiling temperature.
The extent of deviations from the ideal gas law.
The sublimation temperature of a solid.
The vapor pressure of a liquid.
2. Which of the following would you expect to have the highest boiling point?
a.
b.
c.
d.
e.
F2
Cl2
Br2
I2
All of the above have the same boiling point.
3. Which of the following is most likely to be a solid at room temperature?
a.
b.
c.
d.
e.
Na2S
HF
NH3
N2
H2O
4. On a relative basis, the weaker the intermolecular forces in a substance,
a.
b.
c.
d.
e.
the greater its heat of vaporization.
the more it deviates from ideal gas behavior.
the greater its vapor pressure at a particular temperature.
the higher its melting point.
none of these
5. The molecules in a sample of solid SO2 are attracted to each other by a combination of
a.
b.
c.
d.
e.
London forces and H-bonding.
H-bonding and ionic bonding.
covalent bonding and dipole-dipole interactions.
London forces and dipole-dipole interactions.
none of these
6. Which of the following statements about liquids is true?
a. Droplet formation occurs because of the higher stability associated with increased surface
area.
b. Substances that can form hydrogen bonds will display lower melting points than
predicted from periodic trends.
c. London dispersion forces arise from a distortion of the electron clouds within a
molecule or atom.
d. Liquid rise within a capillary tube because of the small size lowers the effective
atmospheric pressure over the surface of the liquid.
e. The boiling point of a solution is dependent solely on the atmospheric pressure over the
solution.
7. In which of the following groups of substances would dispersion forces be the only
significant factors in determining boiling points?
I. Cl2
II.
HF
III.
Ne
IV.
KNO2 V.
CCl4
a.
b.
c.
d.
e.
I, III, V
I, II, III
II, IV
II, V
III, IV, V
8. On the basis of your knowledge of bonding in liquids and solids, arrange the following
substances in order of highest to lowest melting temperature: NaCl, Na, Cl2, SiO2.
a.
b.
c.
d.
e.
Cl2, Na, NaCl, SiO2
Na, NaCl, Cl2, SiO2
SiO2, NaCl, Na, Cl2
NaCl, SiO2, Na, Cl2
SiO2, Na, NaCl, Cl2
9. Knowing that ∆Hvap for water is 40.7 kJ/mol, calculate Pvap of water at 37oC.
a.
b.
c.
d.
e.
6.90 torr
12.4 torr
18.7 torr
25.4 torr
52.6 torr
10. Generally the vapor pressure of a liquid is related to
I. the amount of liquid.
II. atmospheric pressure.
III. temperature.
IV. intermolecular forces.
a.
b.
c.
d.
e.
I, III
II, III, IV
I, III, IV
III, IV
all information is needed
11. A certain solid substance that is very hard, has a high melting point, and is nonconducting
unless melted is most likely to be:
a.
b.
c.
d.
e.
I2
NaCl
CO2
H2O
Cu
12. At normal atmospheric pressure and a temperature of 0oC, which phase(s) of H2O can exist?
a.
b.
c.
d.
e.
ice and water
ice and water vapor
water only
water vapor only
ice only
13. Assume 12,500 J of energy is added to 2.0 moles (36 grams) of H2O as an ice sample at 0oC.
The molar heat of fusion is 6.02 kJ/mol. The specific heat of liquid water is 4.18 J/mol K.
The molar heat of vaporization is 40.6 kJ/mol. The resulting sample contains which of the
following?
a.
b.
c.
d.
e.
only ice
ice and water
only water
water and water vapor
only water vapor
14. The freezing point of helium is -270oC. The freezing point of xenon is -112oC. Both of these
are in the noble gas family. Which of the following statements is supported by these data?
a. Helium and xenon form highly polar molecules.
b. As the molecular weight of the noble gas increases, the freezing point decreases.
c. The London dispersion forces between the helium molecules are greater than the London
dispersion between the xenon molecules.
d. The London dispersion forces between the helium molecules are less than the London
dispersion forces between the xenon molecules.
e. none of these
15. Which of the following processes must exist in equilibrium with the evaporation process
when a measurement of vapor pressure is made?
a.
b.
c.
d.
e.
fusion
vaporization
sublimation
boiling
condensation
16. At room temperature, CsF is expected to be
a. a gas.
b. a conducting solid.
c. a liquid.
d. a brittle solid.
e. a soft solid.
17. A crystal of NaCl is
a.
b.
c.
d.
e.
soft, low melting, a good electrical conductor.
hard, high melting, a good electrical conductor.
soft, low melting, a poor electrical conductor.
hard, high melting, a poor electrical conductor.
soft, high melting, a pool electrical conductor.
18. Given below are the temperatures at which two different liquid compounds with the same
empirical formula have a vapor pressure of 400 torr.
Compound
T(oC)
dimethyl ether, CH3-O-CH3
-37.8
ethanol, CH3CH2OH
63.5
Which of the following statements (a-d) is false?
a. Increasing the temperature will increase the vapor pressure of both liquids.
b. Intermolecular attractive forces are stronger in (liquid) ethanol than in (liquid) dimethyl
ether.
c. The normal boiling point of dimethyl ether will be higher than the normal boiling point
of ethanol.
d. The reason that the temperature at which the vapor pressure is 400 torr is higher for
ethanol (than for dimethyl ether) is that there is strong hydrogen bonding in ethanol.
e. None of these is false.
19. Given the graph below, what is the boiling point of carbon tetrachloride at standard pressure?
a.
b.
c.
d.
e.
60oC
34oC
98oC
77oC
graph does not give that information
20. In which of the following processes will energy be evolved as heat?
a. sublimation
b. crystallization
c. vaporization
d. melting
e. none of these
21. Which of the following is paired incorrectly?
a.
b.
c.
d.
e.
crystalline solids – highly regular arrangement of their components
amorphous solids – considerable disorder in their structures
unit cell – the smallest repeating unit of the lattice
gold metal – simple cubic unit cell
glass – amorphous solid
22. The vapor pressure of water at 100.0oC is
a.
b.
c.
d.
e.
85 torr
760 torr
175 torr
1 torr
More information is needed.
23. How much energy is needed to convert 56.6 grams of ice at 0.00oC to water at 75.0oC?
specific heat (ice) = 2.10 J/g oC
specific heat (water) = 4.18 J/g oC
heat of fusion = 333 J/g
heat of vaporization = 2258 J/g
a.
b.
c.
d.
e.
17.7 kJ
2.03 kJ
27.8 kJ
36.6 kJ
146 kJ
24. How many grams of ice would be melted by the energy obtained as 22.3 g of steam is
condensed at 100oC and cooled to 0oC? Ignore significant figures for this problem.
a.
b.
c.
d.
e.
59675 g
50353 g
179 g
9321 g
28 g
25. A solution containing 402.9 g of Mg(NO3)2 per liter has a density of 1.114 g/mL. The
molarity of the solution is:
a.
b.
c.
d.
e.
2.716 M
2.438 M
8.149 M
3.026 M
none of these
26. How many milliliters of 16.6 M H2SO4 are needed to prepare 600.0 mL of 0.10 M H2SO4?
a.
b.
c.
d.
e.
277 mL
100 mL
3.6 mL
1.8 mL
4.6 mL
27. What volume of a 0.465 M solution of CaCl2 contains 1.28 g of solute?
a.
b.
c.
d.
e.
40.3 mL
24.8 mL
2.75 mL
5.36 mL
75.2 mL
28. Rank the following compounds according to increasing solubility in water.
I. CH3-CH2-CH2-CH3
II. CH3-CH2-O-CH2-CH3
III. CH3-CH2-OH
IV. CH3-OH
a.
b.
c.
d.
e.
I < III < IV < II
I < II < IV < III
III < IV < II < I
I < II < III < IV
No order is correct.
29. Which of the following favors the solubility of an ionic solid in a liquid solvent?
a.
b.
c.
d.
e.
a large magnitude of the solvation energy of the ions
a small magnitude of the lattice energy of the solute
a large polarity of the solvent
all of the above
none of the above
30. Which of the following chemical or physical changes is an endothermic process?
a.
b.
c.
d.
e.
the evaporation of water
the combustion of gasoline
the mixing of sulfuric acid and water
the freezing of water
none of these
31. A salt solution sits in an open beaker. Assuming constant temperature and pressure, the
vapor pressure of the solution
a.
b.
c.
d.
e.
increases over time.
decreases over time.
stays the same over time.
Need to know which salt is in the solution to answer this.
Need to know the temperature and pressure to answer this.
32. Shaving cream is an example of which colloid type?
a.
b.
c.
d.
e.
aerosol
foam
emulsion
sol
coagulate
33. When 0.796 g of NH4NO3 was added to 150.0 g of water in a Styrofoam cup, the temperature
dropped by 0.413oC. The heat capacity of H2O is 4.18 J/goC. Assume the specific heat of
the solution equals that of pure H2O and that the calorimeter neither absorbs nor leaks heat.
The molar heat of solution of solid NH4NO3 is:
a.
b.
c.
d.
e.
+260 J/mol
+26.0 kJ/mol
+2.60 kJ/mol
-2.60 kJ/mol
-260 J/mol
34. Which statement about hydrogen bonding is true?
a. Hydrogen bonding is the intermolecular attractive forces between two hydrogen atoms in
solution.
b. The hydrogen bonding capabilities of water molecules cause CH3CH2CH2CH3 to be more
soluble in water than CH3OH.
c. Hydrogen bonding of solvent molecules with a solute will not affect the solubility of the
solute.
d. Hydrogen bonding interactions between molecules are stronger than the covalent bonds
within the molecule.
e. Hydrogen bonding arises from the dipole moment created by the unequal sharing of
electrons within certain covalent bonds within a molecule.
35. The most likely reason for colloidal dispersion is ________.
a.
b.
c.
d.
e.
the Tyndall effect
coagulation
precipitation
emulsion formation
electrostatic repulsion
36. Calculate the molarity of a solution of magnesium chloride with a concentration of 19.2
mg/mL.
a.
b.
c.
d.
e.
0.403 M
0.202 M
0.101 M
4.96 M
0.321 M