Chapter 11 1 How many compounds, of the ones listed below

Chemistry: A Molecular Approach, 2e (Tro)

Chapter 11 Liquids, Solids, and Intermolecular Forces

Multiple Choice Questions

1) 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

2) 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

3) 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

4) 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

5) 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

6) 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

7) 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.

8) 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

9) The two strands in DNA are held together by ________.

A) dispersion forces

B) dipole-dipole forces

C) hydrogen bonding

D) ion-dipole forces

10) How many compounds, of the ones listed below, have hydrogen bonding?

CH3CH2CH2NH2 CH3CH2NHCH2CH3

(CH3CH2)2NCH2CH3

A) 2

B) 3

C) 1

D) 0

11) 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

12) 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

13) Identify the compound that does not have hydrogen bonding.

A) (CH3)3N

B) H2O

C) CH3OH

D) HF

E) CH3NH2

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

________.

A) viscosity

B) surface tension

C) dipole-dipole force

D) hydrogen bonding

E) capillary action

15) Choose the substance with the lowest viscosity.

A) Cl3CCCl3

B) Cl2CHCH2Cl

C) Cl2CHCHCl2

D) ClCH2CH2Cl

E) Cl3CCHCl2

16) Choose the substance with the highest viscosity.

A) SbCl3

B) AsCl5

C) ICl2

D) BeCl2

E) OCl2

17) 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

18) 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) All of the above.

19) 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.

20) 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

21) 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

22) 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.

23) Which substance below has the strongest intermolecular forces?

A) A2X, ΔHvap= 39.6 kJ/mol

B) BY2, ΔHvap= 26.7 kJ/mol

C) C3X2, ΔHvap= 36.4 kJ/mol

D) DX2, ΔHvap= 23.3 kJ/mol

E) EY3, ΔHvap= 21.5 kJ/mol

24) 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.

25) 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

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

A) SiS2

B) RbCl

C) CH3SCH3

D) BF3

E) SbH3

27) Which of the following substances would you predict to have the highest ΔHvap?

A) CH3Cl

B) HCl

C) HOCH2CH2OH

D) CH3CH2OH

E) CH3CH2CH2CH3

28) How much energy is required to vaporize 48.7 g of dichloromethane (CH2Cl2) at its boiling point, if

its ΔHvap 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

29) How much energy is required to vaporize 98.6 g of ethanol (C2H5OH) at its boiling point, if its

ΔHvap 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

30) 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

31) 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

32) 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

33) 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

34) 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

35) 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

36) Determine ΔHvap 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

37) Determine the normal boiling point of a substance whose vapor pressure is 55.1 mm Hg at 35°C and

has a ΔHvap of 32.1 kJ/mol.

A) 255 K

B) 368 K

C) 412 K

D) 390. K

E) 466 K

38) Determine the vapor pressure (in mm Hg) of a substance at 29°C, whose normal boiling point is

76°C and has a ΔHvap 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

39) Determine the vapor pressure (in torr) of a substance at 36°C, whose normal boiling point is 84°C

and has a ΔHvap of 22.1 kJ/mol.

A) 239 torr

B) 31.8 torr

C) 41.8 torr

D) 147 torr

E) 98 torr

40) 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.

41) 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

42) 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

43) 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

44) At atmospheric pressure, dry ice ________.

A) freezes

B) deposits

C) sublimes

D) melts

E) boils

45) At atmospheric pressure, ice ________.

A) freezes

B) deposits

C) sublimes

D) melts

E) boils

46) 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.

ΔHvap = 40.7 kJ/mol

Cliq = 4.18 J/g∘C

Cgas = 2.01 J/g∘C

Csol = 2.09 J/g∘C

Tmelting = 0∘C

Tboiling = 100∘C

A) 63.5 kJ

B) 87.7 kJ

C) 10.9 kJ

D) 52.7 kJ

E) 91.7 kJ

47) 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.

ΔHvap = 33.9 kJ/mol

ΔHfus = 9.8 kJ/mol

Cliq = 1.73 J/g°C

Cgas = 1.06 J/g°C

Csol = 1.51 J/g°C

Tmelting = 279.0 K

Tboiling = 353.0 K

A) 38.9 kJ

B) 95.4 kJ

C) 67.7 kJ

D) 54.3 kJ

E) 74.4 kJ

48) 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.

ΔHfus = 7.27 kJ/mol

Cliq = 2.16 J/g°C

Cgas = 1.29 J/g°C

Csol = 1.65 J/g°C

Tmelting = -95.0°C

A) 8.48 kJ

B) 18.5 kJ

C) 32.2 kJ

D) 29.4 kJ

E) 9.97 kJ

49) 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.

ΔHvap = 33.9 kJ/mol

ΔHfus = 9.8 kJ/mol

Cliq = 1.73 J/g°C

Cgas = 1.06 J/g°C

Csol = 1.51 J/g°C

Tmelting = 279.0 K

Tboiling = 353.0 K

A) 17.6 kJ

B) 11.8 kJ

C) 70.2 kJ

D) 10.5 kJ

E) 29.4 kJ

50) 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.

13

51) 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 ΔHvap.

E) None of the above are true.

52) 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.

53) Why is water an extraordinary substance?

14

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.

54) Identify the compound with the highest boiling point.

A) CH4

B) NH3

C) HF

D) H2S

E) H2O

55) Determine the radius of an Al atom (in pm) if the density of aluminum is 2.71 g/cm3. Aluminum

crystallizes in a face centered cubic structure with an edge length of 2 r.

A) 143 pm

B) 227 pm

C) 96 pm

D) 172 pm

E) 193 pm

56) A metal crystallizes in a face centered cubic structure and has a density of 11.9 g/cm3. If the radius

of the metal atom is 138 pm, what is the identity of the metal?

A) At

B) Pd

C) Mn

D) Fe

E) Cr

57) Vanadium crystallizes in a body centered cubic structure and has an atomic radius of 131 pm.

Determine the density of vanadium, if the edge length of a bcc structure is 4r/ .

A) 3.06 g/cm3

B) 12.2 g/cm3

C) 6.11 g/cm3

D) 2.77 g/cm3

E) 8.46 g/cm3

58) Identify the type of solid for AgCl.

A) metallic atomic solid

B) ionic solid

C) nonbonding atomic solid

D) molecular solid

E) networking atomic solid

59) Identify the type of solid for ice.

A) metallic atomic solid

B) ionic solid

C) nonbonding atomic solid

D) molecular solid

E) networking atomic solid

60) Identify the type of solid for gold.

A) metallic atomic solid

B) ionic solid

C) nonbonding atomic solid

D) molecular solid

E) networking atomic solid

61) Identify the type of solid for diamond.

A) metallic atomic solid

B) ionic solid

C) nonbonding atomic solid

D) molecular solid

E) networking atomic solid

62) Identify the type of solid for argon.

A) metallic atomic solid

B) ionic solid

C) nonbonding atomic solid

D) molecular solid

E) networking atomic solid

Algorithmic Questions

1) Which has the smallest dipole-dipole forces?

A) CH3Cl

B) HBr

C) O2

D) NO

2) Which is expected to have the largest dispersion forces?

A) C3H8

B) C12H26

C) F2

D) Be Cl2

3) Which of the following compounds exhibits hydrogen bonding?

A) CH3I

B) HBr

C) CH3OCH3

D) CH3NH2

4) 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

5) 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.