Deck 12: Liquids, Solids, and Intermolecular Forces

Question 1

Identify the characteristics of a gas.

A) indefinite shape and volume
B) indefinite shape, but definite volume
C) definite shape and volume
D) none of the above
E) all of the above

Answer 1

indefinite shape and volume

Question 2

The two strands in DNA are held together by

A) dispersion forces.
B) dipole-dipole forces.
C) hydrogen bonding.
D) ion-dipole forces.

Answer 2

hydrogen bonding.

Question 3

What is the strongest type of intermolecular force present in NH₂CH₃?

A) dispersion
B) dipole-dipole
C) hydrogen bonding
D) ion-dipole
E) none of the above

Answer 3

hydrogen bonding

Question 4

Which of the following statements is TRUE?

A) Vapor pressure increases with temperature.
B) Hydrogen bonds are stronger than covalent bonds.
C) Intermolecular forces hold the atoms in molecules together.
D) Dispersion forces are generally stronger than dipole-dipole forces.
E) None of the above are true.

Question 5

Choose the substance with the highest viscosity.

A) water at 10°C
B) water at 20°C
C) water at 30°C
D) water at 40°C
E) water at 50°C

Question 6

Give the change in condition to go from a liquid to a gas.

A) increase heat or reduce pressure
B) increase heat or increase pressure
C) cool or reduce pressure
D) cool or increase pressure
E) none of the above

Question 7

Describe sweating in humans.

A) It is an endothermic reaction.
B) The sweat evaporates absorbing heat from the body.
C) The skin is cooled.
D) None of the above.
E) A, B, and C

Question 8

Identify the place which has the lowest boiling point of water.

A) Death Valley, 282 feet below sea level
B) a pressurized passenger jet, 35,000 feet
C) New Orleans, sea level
D) Mt. Everest, 29,035 feet
E) Denver, Colorado, 5280 feet

Question 9

How many compounds,of the ones listed below,have hydrogen bonding?
CH₃CH₂CH₂NH₂ CH₃CH₂NHCH₂CH₃ (CH₃CH₂)₂NCH₂CH₃

A) 2
B) 3
C) 1
D) 0

Question 10

Which of the following statements is TRUE?

A) Intermolecular forces are generally stronger than bonding forces.
B) The potential energy of molecules decrease as they get closer to one another.
C) Energy is given off when the attraction between two molecules is broken.
D) Increasing the pressure on a solid usually causes it to become a liquid.
E) None of the above are true.

Question 11

Which one of the following has a low density?

A) gas
B) liquid
C) solid
D) none of the above
E) all of the above

Question 12

The forces between polar molecules is known as

A) hydrogen bonding.
B) ion-dipole forces.
C) dipole-dipole forces.
D) dispersion forces.
E) ionic forces.

Question 13

Place the following compounds in order of decreasing strength of intermolecular forces. I.CH₃CH₂CH₂CH₂CH₂CH₃ II.(CH₃)₃CCH₃ III.(CH₃)₃CCH₂CH₃

A) III > II > I
B) I > III > II
C) I > II > III
D) II > III > I
E) III > I > II

Question 14

Which one of the following has a definite shape and volume?

A) gas
B) liquid
C) solid
D) none of the above
E) all of the above

Question 15

Identify the term used to describe the ability of a liquid to flow against gravity up a narrow tube.

A) capillary action
B) viscosity
C) surface tension
D) density
E) none of the above

Question 16

Identify the compound that does not have hydrogen bonding.

A) (CH₃)₃N
B) H₂O
C) CH₃OH
D) HF
E) CH₃NH₂

Question 17

In a liquid,the energy required to increase the surface area by a unit amount is called

A) viscosity.
B) surface tension.
C) dipole-dipole force.
D) hydrogen bonding.
E) capillary action.

Question 18

Identify the characteristics of a liquid.

A) indefinite shape and volume
B) indefinite shape, but definite volume
C) definite shape and volume
D) none of the above
E) all of the above

Question 19

Choose the substance with the lowest viscosity.

A) Cl₃CCCl₃
B) Cl₂CHCH₂Cl
C) Cl₂CHCHCl₂
D) ClCH₂CH₂Cl
E) Cl₃CCHCl₂

Question 20

Place the following compounds in order of increasing strength of intermolecular forces. CH₄ CH₃CH₂CH₃ CH₃CH₃

A) CH₃CH₂CH₃ < CH₄ < CH₃CH₃
B) CH₃CH₂CH₃ < CH₃CH₃ < CH₄
C) CH₃CH₃ < CH₄ < CH₃CH₂CH₃
D) CH₄ < CH₃CH₂CH₃ < CH₃CH₃
E) CH₄ < CH₃CH₃ < CH₃CH₂CH₃

Question 21

Place the following substances in order of decreasing boiling point. N₂ O₂ H₂

A) O₂ > H₂ > N₂
B) N₂ > H₂ > O₂
C) N₂ > O₂ > H₂
D) O₂ > N₂ > H₂
E) H₂ > N₂ > O₂

Question 22

Determine the vapor pressure (in torr)of a substance at 36°C,whose normal boiling point is 84°C and has a ΔH_vap of 22.1 kJ/mol.

A) 239 torr
B) 31.8 torr
C) 41.8 torr
D) 147 torr
E) 98 torr

Question 23

Which of the following substances would you predict to have the highest ΔH_vap?

A) CH₃Cl
B) HCl
C) HOCH₂CH₂OH
D) CH₃CH₂OH
E) CH₃CH₂CH₂CH₃

Question 24

Place the following substances in order of decreasing vapor pressure at a given temperature. BeF₂ CH₃OH OF₂

A) CH₃OH > OF₂ > BeF₂
B) BeF₂ > OF₂ > CH₃OH
C) OF₂ > CH₃OH > BeF₂
D) OF₂ > BeF₂ > CH₃OH
E) BeF₂ > CH₃OH > OF₂

Question 25

Place the following substances in order of increasing vapor pressure at a given temperature. NF₃ NH₃ BCl₃

A) NH₃ < NF₃ < BCl₃
B) NF₃ < NH₃ < BCl₃
C) BCl₃ < NF₃ < NH₃
D) NH₃ < BCl₃ < NF₃
E) BCl₃ < NH₃ < NF₃

Question 26

Define deposition.

A) A liquid becomes a gas.
B) A gas becomes a liquid.
C) A gas becomes a solid.
D) A solid becomes a gas.
E) A solid becomes a liquid.

Question 27

Define boiling.

A) A liquid becomes a gas.
B) A gas becomes a liquid.
C) A gas becomes a solid.
D) A solid becomes a gas.
E) A solid becomes a liquid.

Question 28

How much energy is required to vaporize 98.6 g of ethanol (C₂H₅OH)at its boiling point,if its ΔH_vap is 40.5 kJ/mol?

A) 86.7 kJ
B) 11.5 kJ
C) 18.9 kJ
D) 52.8 kJ
E) 39.9 kJ

Question 29

Determine the vapor pressure (in mm Hg)of a substance at 29°C,whose normal boiling point is 76°C and has a ΔH_vap of 38.7 kJ/mol.

A) 80 mm Hg
B) 13 mm Hg
C) 21 mm Hg
D) 48 mm Hg
E) 96 mm Hg

Question 30

Which of the following statements is FALSE?

A) The rate of vaporization increases with increasing surface area.
B) The rate of vaporization increases with decreasing strength of intermolecular forces.
C) The rate of vaporization increases with increasing temperature.
D) Molecules with hydrogen bonding are more volatile than compounds with dipole-dipole forces.
E) None of the above are false.

Question 31

How much energy is required to vaporize 48.7 g of dichloromethane (CH₂Cl₂)at its boiling point,if its ΔH_vap is 31.6 kJ/mol?

A) 31.2 kJ
B) 6.49 kJ
C) 55.1 kJ
D) 15.4 kJ
E) 18.1 kJ

Question 32

Determine the normal boiling point of a substance whose vapor pressure is 55.1 mm Hg at 35°C and has a ΔH_vap of 32.1 kJ/mol.

A) 255 K
B) 368 K
C) 412 K
D) 390. K
E) 466 K

Question 33

Identify the place which has the highest boiling point of water.

A) Death Valley, 282 feet below sea level
B) a pressurized passenger jet, 35,000 feet
C) New Orleans, sea level
D) Mt. Everest, 29035 feet
E) Denver, Colorado, 5280 feet

Question 34

Which substance below has the strongest intermolecular forces?

A) A₂X, ΔH_vap= 39.6 kJ/mol
B) BY₂, ΔH_vap= 26.7 kJ/mol
C) C₃X₂, ΔH_vap= 36.4 kJ/mol
D) DX₂, ΔH_vap= 23.3 kJ/mol
E) EY₃, ΔH_vap= 21.5 kJ/mol

Question 35

Determine ΔH_vap for a compound that has a measured vapor pressure of 24.3 torr at 273 K and 135 torr at 325 K.

A) 41 kJ/mol
B) 79 kJ/mol
C) 24 kJ/mol
D) 13 kJ/mol
E) 34 kJ/mol

Question 36

Place the following substances in order of increasing vapor pressure at a given temperature. SF₆ SiH₄ SF₄

A) SF₆ < SiH₄ < SF₄
B) SiH₄ < SF₄ < SF₆
C) SF₆ < SF₄ < SiH₄
D) SF₄ < SF₆ < SiH₄
E) SiH₄ < SF₆ < SF₄

Question 37

Choose the substance with the highest vapor pressure at a given temperature.

A) SiS₂
B) RbCl
C) CH₃SCH₃
D) BF₃
E) SbH₃

Question 38

Place the following substances in order of decreasing boiling point. H₂O N₂ CO

A) CO > H₂O > N₂
B) N₂ > CO > H₂O
C) H₂O > CO > N₂
D) CO > N₂ > H₂O
E) N₂ > H₂O > CO

Question 39

Give the term for the temperature at which the gas and liquid phases form a supercritical fluid.

A) absolute temperature
B) definite temperature
C) fluid temperature
D) critical temperature
E) solid temperature

Question 40

Place the following substances in order of decreasing vapor pressure at a given temperature. PF₅ BrF₃ CF₄

A) BrF₃ > PF₅ > CF₄
B) BrF₃ > CF₄ > PF₅
C) PF₅ > BrF₃ > CF₄
D) CF₄ > BrF₃ > PF₅
E) CF₄ > PF₅ > BrF₃

Question 41

What happens when the vapor pressure of a liquid is equal to the external pressure?

A) An equilibrium exists between the liquid and the solid state.
B) The liquid freezes.
C) The intermolecular forces become stronger in the liquid.
D) The liquid boils.
E) Dispersion forces become weaker in the liquid.

Question 42

Calculate the energy that is required to change 50.0 g ice at -30.0°C to a liquid at 73.0°C.The heat of fusion = 333 J/g,the heat of vaporization = 2256 J/g,and the specific heat capacities of ice = 2.06 J /gK and liquid water = 4.184 J /gK.

A) 3.50 × 10⁴ J
B) 2.14 × 10⁴ J
C) 1.31 × 10⁵ J
D) 6.59 × 10³ J
E) 1.66 × 10⁴ J

Question 43

How much energy is required to heat 87.1 g acetone (molar mass=58.08 g/mol)from a solid at -154.0°C to a liquid at -42.0°C? The following physical data may be useful.
ΔH_fus = 7.27 kJ/mol
C_liq = 2.16 J/g°C
C_gas = 1.29 J/g°C
C_sol = 1.65 J/g°C
T_melting = -95.0°C

A) 8.48 kJ
B) 18.5 kJ
C) 32.2 kJ
D) 29.4 kJ
E) 9.97 kJ

Question 44

The normal boiling point of diethyl ether is 34.6°C.At a pressure of 1.3 atm,the boiling point

A) > 34.6°C.
B) <34.6 °C.
C) 34.6°C.
D) There is not information given to solve the problem.

Question 45

Define sublimation.

A) the phase transition from solid to gas
B) the phase transition from gas to solid
C) the phase transition from gas to liquid
D) the phase transition from liquid to gas
E) the phase transition from liquid to solid

Question 46

The set of conditions at which point a phase boundary no longer exists is know as the

A) freezing point.
B) critical point.
C) melting point.
D) boiling point.
E) sublimation point.

Question 47

Identify the compound with the highest boiling point.

A) CH₄
B) NH₃
C) HF
D) H₂S
E) H₂O

Question 48

The boiling point of H₂O is much higher than that of the analogous molecule H₂S.This is mostly due to

A) dispersion forces being much stronger in H₂S than in H₂O.
B) dipole-dipole forces being much stronger in H₂S than in H₂O.
C) hydrogen bonding being much stronger in H₂S than in H₂O.
D) dipole-dipole forces being much stronger in H₂O than in H₂S.
E) hydrogen bonding being much stronger in H₂O than in H₂S.

Question 49

How much energy must be removed from a 125 g sample of benzene (molar mass= 78.11 g/mol)at 425.0 K to liquify the sample and lower the temperature to 335.0 K? The following physical data may be useful.
ΔH_vap = 33.9 kJ/mol
ΔH_fus = 9.8 kJ/mol
C_liq = 1.73 J/g°C
C_gas = 1.06 J/g°C
C_sol = 1.51 J/g°C
T_melting = 279.0 K
T_boiling = 353.0 K

A) 38.9 kJ
B) 95.4 kJ
C) 67.7 kJ
D) 54.3 kJ
E) 74.4 kJ

Question 50

Why is water an extraordinary substance?

A) Water has a low molar mass, yet it is a liquid at room temperature.
B) Water is the main solvent within living organisms.
C) Water has an exceptionally high specific heat capacity.
D) Water has strong hydrogen bonding.
E) All of the above

Question 51

At atmospheric pressure,ice

A) freezes.
B) deposits.
C) sublimes.
D) melts.
E) boils.

Question 52

Propanol has a normal boiling point of 97.8°C.At 400 torr,it has a boiling point of 82.0°C.What is the heat of vaporization?

A) 24.9 kJ/mol
B) 38.7 kJ/mol
C) 12.3 kJ/mol
D) 52.7 kJ/mol
E) 44.4 kJ/mol

Question 53

At atmospheric pressure,dry ice

A) freezes.
B) deposits.
C) sublimes.
D) melts.
E) boils.

Question 54

Which of the following must be overcome during the boiling of acetonitrile,CH₃CN?
1)dispersion forces
2)dipole-dipole forces
3)hydrogen bonds

A) 1 only
B) 2 only
C) 1 and 2
D) 1 and 3
E) 1, 2, and 3

Question 55

How much energy must be removed from a 94.4 g sample of benzene (molar mass= 78.11 g/mol)at 322.0 K to solidify the sample and lower the temperature to 205.0 K? The following physical data may be useful.
ΔH_vap = 33.9 kJ/mol
ΔH_fus = 9.8 kJ/mol
C_liq = 1.73 J/g°C
C_gas = 1.06 J/g°C
C_sol = 1.51 J/g°C
T_melting = 279.0 K
T_boiling = 353.0 K

A) 17.6 kJ
B) 11.8 kJ
C) 70.2 kJ
D) 10.5 kJ
E) 29.4 kJ

Question 56

In which of the following substances should hydrogen bonding contribute to the attractive interactions in the molecules?

A) CF₄
B) HI
C) H₂Se
D) N(CH₃)₃
E) None of the above

Question 57

The resistance of a liquid to flow is known as

A) surface tension.
B) meniscus.
C) viscosity.
D) capillary action.
E) intermolecular forces.

Question 58

Define freezing.

A) the phase transition from solid to gas
B) the phase transition from gas to solid
C) the phase transition from gas to liquid
D) the phase transition from liquid to gas
E) the phase transition from liquid to solid

Question 59

How much energy is required to heat 36.0 g H₂O from a liquid at 65°C to a gas at 115°C? The following physical data may be useful.
ΔH_vap = 40.7 kJ/mol
C_liq = 4.18 J/g°C
C_gas = 2.01 J/g°C
C_sol = 2.09 J/g°C
T_melting = 0°C
T_boiling = 100°C

A) 63.5 kJ
B) 87.7 kJ
C) 10.9 kJ
D) 52.7 kJ
E) 91.7 kJ

Question 60

Define fusion.

A) the phase transition from solid to liquid
B) the phase transition from gas to solid
C) the phase transition from gas to liquid
D) the phase transition from liquid to gas
E) the phase transition from liquid to solid

Question 61

Consider the phase diagram shown.What is the normal freezing point?

A) 31°C
B) -56.7 °C
C) -78.5 °C
D) 0°C
E) 100°C

Question 62

The heat required to melt 1 mol of a solid is known as the

A) melting point.
B) heat of fusion.
C) freezing point.
D) heat of vaporization.
E) critical point.

Question 63

Consider the phase diagram below.If the dashed line at 1 atm of pressure is followed from 100 to 500°C,what phase changes will occur (in order of increasing temperature)?

A) condensation, followed by vaporization
B) sublimation, followed by deposition
C) vaporization, followed by deposition
D) fusion, followed by vaporization
E) No phase change will occur under the conditions specified.

Question 64

Which of the following compounds exhibits hydrogen bonding?

A) CH₃I
B) HBr
C) CH₃OCH₃
D) CH₃NH₂

Question 65

Which of the following compounds has dipole-dipole interactions as the strongest intermolecular force?

A) Br₂
B) CH₃Br
C) CBr₄
D) BrCH₂CH₂OH

Question 66

Consider the phase diagram shown.What is the triple point?

A) 72.9 atm, 31 °C
B) 5.1 atm, -56.7 °C
C) 1 atm, -78.5 °C
D) 5.1 atm, 31 °C
E) 72.9 atm, -56.7 °C

Question 67

The heat of vaporization of acetone is 31.3 kJ/mol,and a a boiling point of 78.6° at 1520 mm Hg.What is the boiling point when the pressure is raised to 7600 mm Hg?

A) 211°C
B) 182°C
C) 83.5°C
D) 141°C
E) 118°C

Question 68

What is the strongest type of intermolecular force present in Cl₂?

A) ion-dipole
B) dipole-dipole
C) dispersion
D) hydrogen bonding
E) none of the above

Question 69

An unknown substance has a boiling point of 150°C at 650 torr,and a boiling point of 195°C at 780 torr.What is the heat of vaporization?

A) 22.2 kJ/mol
B) 12.6 kJ/mol
C) 6.67 kJ/mol
D) 29.4 kJ/mol
E) 18.4 kJ/mol

Question 70

Consider the phase diagram shown.Choose the statement below that is TRUE.

A) The triple point of this substance occurs at a temperature of 31°C.
B) At 10 atm of pressure, there is no temperature where the liquid phase of this substance would exist.
C) The solid phase of this substance is higher in density than the liquid phase.
D) The line separating the solid and liquid phases represents the ΔH_vap.
E) None of the above are true.

Question 71

The normal boiling point for H₂Se is higher than the normal boiling point for H₂S .This can be explained by

A) larger dipole-dipole forces for H₂Se .
B) larger dispersion forces for H₂Se .
C) larger hydrogen-bond forces for H₂Se .
D) larger dipole-dipole forces, larger dispersion forces, and larger hydrogen-bond forces for H₂Se .

Question 72

Which is expected to have the largest dispersion forces?

A) C₃H₈
B) C₁₂H₂₆
C) F₂
D) Be Cl₂

Question 73

Consider the phase diagram shown.What is the normal boiling point?

A) 31°C
B) -56.7 °C
C) -78.5 °C
D) 0°C
E) 100°C

Question 74

List the compounds in decreasing boiling point order. CH₃CH₂CH₃ Ar CH₃CN

A) CH₃CH₂CH₃ > CH₃CN > Ar
B) Ar > CH₃CH₂CH₃ > CH₃CN
C) CH₃CH₂CH₃ > Ar > CH₃CN
D) CH₃CN > CH₃CH₂CH₃ > Ar
E) Ar > CH₃CN > CH₃CH₂CH₃

Question 75

In liquid propanol, CH₃CH₂CH₂OH
Which intermolecular forces are present?

A) Dispersion, hydrogen bonding and dipole-dipole forces are present.
B) Only dipole-dipole and ion-dipole forces are present.
C) Only dispersion and dipole-dipole forces are present.
D) Only hydrogen bonding forces are present.

Question 76

Which has the smallest dipole-dipole forces?

A) CH₃Cl
B) HBr
C) O₂
D) NO

Question 77

Describe the differences in the meniscuses of water and mercury.

A) Both have concave meniscuses.
B) Both have convex meniscuses.
C) Water has a convex meniscus while mercury has a concave meniscus.
D) Water has a concave meniscus while mercury has a convex meniscus.
E) Neither has a meniscus.

Question 78

Define triple point.

A) The temperature, pressure, and density for a gas.
B) The temperature at which the boiling point equals the melting point.
C) The temperature and pressure where liquid, solid, and gas are equally stable and are in equilibrium.
D) The temperature that is unique for a substance.
E) The temperature at which the solid and liquid co-exist.

Question 79

What is the strongest type of intermolecular force present in CH₂F₂?

A) dispersion
B) dipole-dipole
C) hydrogen bonding
D) ion-dipole
E) none of the above

Question 80

Calculate the energy that is required to heat 125 g ice at -10.0°C to a temperature of 130.0°C.The heat of fusion = 333 J/g,the heat of vaporization = 2256 J/g,and the specific heat capacities of ice = 2.06 J /g∙K,liquid water = 4.184 J /g∙K,and steam = 2.01 J /g∙K.

A) 4.75 × 10⁶ J
B) 3.87 × 10⁵ J
C) 1.31 × 10⁵ J
D) 7.32 × 10⁴ J
E) 2.88 × 10⁴ J