Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which of the following is most likely not a gas at room temperature?
A) H2
B) Cl2
C) HCl
D) LiCl
E) CH4
1)
2) The kinetic-molecular theory predicts that pressure rises as the temperature of a gas increases
because __________.
A) the gas molecules collide more frequently with the wall
B) the gas molecules collide more energetically with the wall
C) the gas molecules collide less frequently with the wall
D) the average kinetic energy of the gas molecules decreases
E) both the gas molecules collide more frequently with the wall and the gas molecules collide
more energetically with the wall
2)
3) According to kinetic-molecular theory, in which of the following gases will the root-mean-square
speed of the molecules be the highest at 200°C?
A) Cl2
3)
B) H2 O
C) HCl
D) SF6
E) None. The molecules of all gases have the same root-mean-square speed at any given
temperature.
4) At 333 K, which of the pairs of gases below would have the most nearly identical rates of effusion?
A) CO and N2
4)
B) NO2 and N2 O4
C) CO and CO2
D) N2 O and NO2
E) N2 and O2
5) Which noble gas is expected to show the largest deviations from the ideal gas behavior?
A) argon
B) xenon
C) neon
D) helium
E) krypton
5)
6) The van der Waals equation for real gases recognizes that __________.
A) the molecular attractions between particles of gas decreases the pressure exerted by the gas
B) gas particles have non-zero volumes and interact with each other
C) molar volumes of gases of different types are different
D) the non-zero volumes of gas particles effectively decrease the amount of "empty space"
between them
E) all of the above statements are true
6)
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7) When NaCl dissolves in water, aqueous Na+ and Cl- ions result. The force of attraction that exists
between Na+ and H2O is called a(n) __________ interaction.
7)
8) Which one of the following derivatives of ethane has the highest boiling point?
A) C2 F6
B) C2 I6
C) C2 H6
D) C2 Cl6
8)
A) ion-ion
B) dipole-dipole
C) hydrogen bonding
D) ion-dipole
E) London dispersion force
E) C2 Br6
9) The intermolecular force(s) responsible for the fact that CH4 has the lowest boiling point in the set
CH4, SiH4 , GeH4, SnH4 is/are __________.
9)
A) London dispersion forces
B) mainly hydrogen bonding but also dipole-dipole interactions
C) dipole-dipole interactions
D) hydrogen bonding
E) mainly London-dispersion forces but also dipole-dipole interactions
10) The shape of a liquid's meniscus is determined by __________.
A) the type of material the container is made of
B) the relative magnitudes of cohesive forces in the liquid and adhesive forces between the
liquid and its container
C) the volume of the liquid
D) the amount of hydrogen bonding in the liquid
E) the viscosity of the liquid
10)
11) Based on the figure above, the boiling point of ethyl alcohol under an external pressure of
0.0724 atm is __________°C.
A) 60
B) 20
C) 70
D) 40
E) 80
11)
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12) The enthalpy change for converting 10.0 g of ice at -25.0°C to water at 80.0°C is __________ kJ. The
specific heats of ice, water, and steam are 2.09 J/g-K, 4.18 J/g-K, and 1.84 J/g-K, respectively. For
H2 O, Hfus = 6.01 kJ/mol, and Hvap = 40.67 kJ/mol
12)
13) On a phase diagram, the critical temperature is __________.
A) the temperature below which a gas cannot be liquefied
B) the temperature at which all three states are in equilibrium
C) the temperature required to cause sublimation of a solid
D) the temperature above which a gas cannot be liquefied
E) the temperature required to melt a solid
13)
14)
14)
A) 9.88
B) 6.16
C) 12.28
D) 7.21
E) 3870
In the manometer connected to the flask, the left side reads 98.3 mm, and the right (inner)
side reads 32.1 mm. The pressure in the laboratory is 756.2 mm Hg. What is the
pressure of the sample gas in torr?
A) 822.4 torr
B) 66.2 torr
C) 756.2 torr
D) 98.3 torr
15) A 5.00-L sample of gas in a piston chamber at 25 oC is heated to 100 oC, while the pressure is
maintained at 1.00 atm. What is the new volume of the gas after heating?
A) 6.26 L
B) 20.0 L
C) 5.00 L
D) 626 L
15)
16) Name the kind or kinds of intermolecular forces that must be overcome to convert HCN from
liquid to gas:
A) London dispersion force and dipole dipole interaction
B) only Londaon dispersion forces
C) only dipole - dipole interaction
D) London dispersion and hydrogen bonding
16)
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ESSAY. Write your answer in the space provided or on a separate sheet of paper.
17) A 97.6 mL sample of hydrogen gas is collected by water displacement at 20.0 oC. The pressure of the collected
gas which is the same as the atmospheric pressure in the laboratory is measured to be 769.5 torr. How many
milligrams of hydrogen does the sample contain? The tabulated value of the vapor pressure of water at 20.0 oC
is 17.5 torr.
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