11.2 Bimodal Questions
1) Based on molecular mass and dipole moment of the five compounds in the table below, which should
have the highest boiling point?
A) CH3CH2CH3
B) CH3OCH3
C) CH3Cl
D) CH3CHO
E) CH3CN
2) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it
was heated. The slope of the ________ segment corresponds to the heat capacity of the liquid of the
substance.
A) AB
B) BC
C) CD
D) DE
E) EF
3) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it
was heated. The slope of the ________ segment corresponds to the heat capacity of the solid.
A) AB
B) BC
C) CD
D) DE
E) EF
4) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it
was heated. The slope of the ________ segment corresponds to the heat capacity of the gas.
A) AB
B) BC
C) CD
D) DE
E) EF
5) The heating curve shown was generated by measuring the heat flow and temperature of a solid as it
was heated. The heat flow into the sample in the segment ________ will yield the value of the ΔHvap of
this substance.
A) AB
B) BC
C) CD
D) DE
E) EF
6) The heating curve shown was generated by measuring the heat flow and temperature of a solid as it
was heated. The heat flow into the sample in the segment ________ will yield the value of the ΔHfusion
of this substance.
A) AB
B) BC
C) CD
D) DE
E) EF
7) On the phase diagram shown above, segment ________ corresponds to the conditions of temperature
and pressure under which the solid and the gas of the substance are in equilibrium.
A) AB
B) AC
C) AD
D) CD
E) BC
8) On the phase diagram shown above, the coordinates of point ________ correspond to the critical
temperature and pressure.
A) A
B) B
C) C
D) D
E) E
9) On the phase diagram shown above, the coordinates of point ________ correspond to the triple point.
A) A
B) B
C) C
D) D
E) E
10) The phase diagram of a substance is given above. The region that corresponds to the solid phase is
________.
A) w
B) x
C) y
D) z
E) x and y
11) The normal boiling point of the substance with the phase diagram shown above is ________ °C.
A) 10
B) 20
C) 30
D) 40
E) 50
12) The normal melting point of the substance with the phase diagram shown above is ________ °C.
A) 15
B) 25
C) 35
D) 45
E) 55
13) The phase diagram of a substance is shown above. The area labeled ________ indicates the gas phase
for the substance.
A) w
B) x
C) y
D) z
E) y and z
14) The phase diagram of a substance is shown above. The area labeled ________ indicates the solid phase
for the substance.
A) w
B) x
C) y
D) z
E) y and z
15) The phase diagram of a substance is shown above. The area labeled ________ indicates the liquid
phase for the substance.
A) w
B) x
C) y
D) z
E) y and z
16) According to the phase diagram shown above, the normal boiling point of this substance is ________
°C.
A) -3
B) 10
C) 29
D) 38
E) 0
17) According to the phase diagram shown above, the normal melting point of this substance is ________
°C.
A) –13
B) 10
C) 29
D) 38
E) 0
18) A ________ liquid crystal has the least order and is the most liquid-like.
A) nematic
B) smectic
C) cholesteric
D) smectic B
E) smectic C
19) Which type of liquid crystal is colored and changes color with temperature?
A) nematic
B) smectic A
C) cholesteric
D) smectic B
E) smectic C
11.3 Algorithmic Questions
1) As a gaseous element condenses, the atoms become ________ and they have ________ attraction for one
another.
A) less separated, more
B) less separated, less
C) more separated, more
D) more separated, less
E) smaller, lesser
2) What is the predominant intermolecular force in BaBr2?
A) ionic bonding
B) ion-dipole attraction
C) dipole-dipole attraction
D) hydrogen bonding
E) London-dispersion forces
3) With what compound will NH3 experience only dispersion intermolecular forces?
A) BF3
B) LiF
C) CH3I
D) CH3OH
E) HCN
4) With what compound will NH3 experience only ion-dipole intermolecular forces?
A) LiCl
B) SiH4
C) CH3I
D) C3H7OH
E) OCl2
5) Which one of the following exhibits dipole-dipole attraction between molecules?
A) AsH3
B) CBr4
C) SiO2
D) Cl2
E) BH3
6) Which one of the following exhibits dipole-dipole attraction between molecules?
A) NH3
B) CF4
C) C10H22
D) O2
E) SF6
7) Of the following substances, only ________ has London dispersion forces as its only intermolecular
force.
A) CCl4
B) SnF3
C) CH3OH
D) HI
E) H2O
8) Of the following substances, only ________ has London dispersion forces as its only intermolecular
force.
A) SiBr4
B) PF3
C) C4H9COOH
D) HCl
E) Cl2O
9) Which one of the following should have the lowest boiling point?
A) CF4
B) SnF3
C) C4H9OH
D) HCl
E) F2O
10) Which one of the following should have the lowest boiling point?
A) CH4
B) PCl3
C) C2H5COOH
D) LiCl
E) Cl2S
11) Of the following substances, ________ has the highest boiling point.
A) H2O
B) SiH4
C) Ar
D) Cl2
E) BF3
12) Of the following substances, ________ has the highest boiling point.
A) HOCH2CH2CH2OH
B) CH3CH2OH
C) C4H10
D) N2
E) Cl2
13) Of the following substances, ________ has the highest boiling point.
A) Br2
B) N2
C) Cl2
D) O2
E) H2
14) Which one of the following derivatives of methane has the highest boiling point?
A) CI4
B) CBr4
C) CCl4
D) CF4
E) CH4
15) What is the predominant intermolecular force in CH4?
A) London-dispersion forces
B) ion-dipole attraction
C) ionic bonding
D) dipole-dipole attraction
E) hydrogen bonding
16) What is the predominant intermolecular force in H2NNH2?
A) hydrogen bonding
B) ion-dipole attraction
C) ionic bonding
D) dipole-dipole attraction
E) London-dispersion forces
17) What is the predominant intermolecular force in HCN?
A) dipole-dipole attraction
B) ion-dipole attraction
C) ionic bonding
D) hydrogen bonding
E) London dispersion forces
18) Ethanol melts at -114 °C and boils at 78 °C at a constant pressure of 1 atm. What state of matter must a
sample of ethanol be in at 0°C and 1 atm?
A) liquid
B) gas
C) solid
D) solid and liquid in equilibrium
E) liquid and gas in equilibrium
19) Boron triiodide (BI3) melts at 49.9 °C and boils at 209.5 °C at a constant pressure of 1 atm. What state
of matter must a sample of boron triiodide be in at 100°C and 1 atm?
A) liquid
B) gas
C) solid
D) solid and liquid in equilibrium
E) liquid and gas in equilibrium
20) The enthalpy change for converting 1.00 mol of ice at -25.0 °C to water at 50.0 °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 H2O,
ΔHfus = 6.01 kJ/mol, and ΔHvap = 40.67 kJ/mol.
A) 12.28
B) 6.27
C) 10.71
D) 4709
E) 8.83
21) The enthalpy change for converting 10.0 g of ice at -50.0 °C to water at 50.0 °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 H2O,
ΔHfus = 6.01 kJ/mol, and ΔHvap = 40.67 kJ/mol.
A) 12.28
B) 4.38
C) 3138
D) 6.47
E) 9.15
22) The heat of fusion of water is 6.01 kJ/mol. The heat capacity of liquid water is 75.3 J/mol ∙ K. The
conversion of 50.0 g of ice at 0.00 °C to liquid water at 0.00°C requires ________ kJ of heat.
A) 6.01
B) 16.7
C) 75.3
D) 17.2
E) Insufficient data are given.
23) Calculate the enthalpy change (in kJ) associated with the conversion of 25.0 grams of ice at -4.00 °C to
water vapor at 109.0 °C. 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 H2O, ΔHfus = 6.01 kJ/mol and ΔHvap = 40.67 kJ/mol.
A) 64.8
B) 75.9
C) 11100
D) 12000
E) 112
24) Ethanol (C2H5OH) melts at -114 °C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid
and liquid ethanol are 0.97 J/g-K and 2.3 J/g-K, respectively. How much heat (kJ) is needed to convert 25.0
g of solid ethanol at -135 °C to liquid ethanol at -60 °C?
A) 207.3
B) -13.3
C) 6.34
D) 3617
E) 8.63
25) Of the following, ________ is the most volatile.
A) C2H6
B) C2I6
C) C2Br6
D) C2Cl6
E) C2F6
26) Of the following, ________ is the least volatile.
A) CI4
B) CF4
C) CBr4
D) CCl4
E) CH4
27) Based on the figure above, the boiling point of diethyl ether under an external pressure of 0.605 atm is
________ °C.
A) 40
B) 10
C) 30
D) 20
E) 0
28) Based on the figure above, the boiling point of ethyl alcohol under an external pressure of 0.658 atm is
________ °C.
A) 20
B) 40
C) 60
D) 80
E) 70
29) Based on the figure above, the boiling point of water under an external pressure of 0.211 atm is
________ °C.
A) 60
B) 40
C) 70
D) 80
E) 90
30) The phase diagram of a substance is given above. This substance is a ________ at 30 °C and 0.5 atm.
A) liquid
B) gas
C) solid
D) supercritical fluid
E) crystal
11.4 Short Answer Questions
1) In general, intramolecular forces determine the ________ properties of a substance and intermolecular
forces determine its ________ properties.
2) London Dispersion Forces tend to ________ in strength with increasing molecular weight.
3) The direct conversion of a solid to a gas is called ________.
4) The initial discovery of a liquid crystal resulted from studies on what compound?
1) The principal source of the difference in the normal boiling points of ICl (97 °C; molecular mass
162 amu) and Br2 (59 °C; molecular mass 160 amu) is both dipole-dipole interactions and London
dispersion forces.
2) The boiling points of normal hydrocarbons are higher than those of branched hydrocarbons of similar
molecular weight because the London-dispersion forces between normal hydrocarbons are greater than
those between branched hydrocarbons.
3) Heats of vaporization are greater than heats of fusion.
4) Under ordinary conditions, a substance will sublime rather than melt if its triple point occurs at a
pressure above atmospheric pressure.
5) Molecules containing only single bonds do not exhibit liquid–crystal behavior because free rotation can
occur around single bonds making these molecules flexible.