Chapter 11 1 The Fraction Molecules With Enough Energy Escape

Chapter 11 – States of Matter: Liquids and Solids

1. Which of the following statements concerning liquids is incorrect?

A)

The volume of a liquid changes very little with pressure.

B)

Liquids are relatively incompressible.

C)

Liquid molecules move slowly compared to solids.

D)

Non-volatile liquids have low vapor pressures at room temperature.

E)

The molecules of a liquid are in constant random motion.

2. Which of the following statements concerning solids, liquids and gases is/are correct?

1.

The close contact of the particles in a solid prevents all possible motion,

including vibrational motion.

2.

Liquids and gases are both considered fluids.

3.

The postulate from kinetic-molecular theory that the particles in a gas are in

constant random motion is equally applicable to liquids, except the particles

are more tightly packed in a gas.

A)

1 only

B)

2 only

C)

3 only

D)

1 and 2

E)

2 and 3

3. What is the name for the following phase change?

I2(s) → I2(g)

A)

sublimation

B)

freezing

C)

vaporization

D)

condensation

E)

melting

4. Which of the following processes is endothermic?

A)

melting of ice

B)

condensation of water

C)

deposition of carbon dioxide

D)

freezing of water

E)

condensation of ammonia

5. The process represented by the equation C10H8(s) → C10H8(g) is

A)

melting.

B)

liquefaction.

C)

sublimation.

D)

condensation.

E)

fusion.

6. When a solid undergoes a phase change to a gas, the process is called

A)

fusion.

B)

condensation.

C)

melting.

D)

vaporization.

E)

sublimation.

7. A bottle is filled with a small amount of a volatile liquid and sealed. Sometime later it is

observed that no liquid is evident in the sealed bottle. Which of the following statements

would explain this observation?

A)

More time is needed to establish equilibrium.

B)

Liquid and vapor are at equilibrium in the bottle.

C)

Too little liquid was added to achieve a liquid vapor equilibrium in the closed

system.

D)

The vapor state is favored when equilibrium is established.

E)

The liquid has undergone sublimation.

8. Enough of a volatile liquid is placed in a closed container to achieve a liquid-vapor

equilibrium at a fixed temperature. Which of the following statements regarding this system

is/are correct once equilibrium is established?

1.

Liquid molecules are no longer evaporating.

2.

The number of vapor molecules remains essentially constant.

3.

The partial pressure exerted by the vapor molecules is called the vapor

pressure of the liquid.

A)

1 only

B)

2 only

C)

3 only

D)

1 and 2

E)

2 and 3

9. Enough of a volatile liquid is placed in a closed container to achieve a liquid-vapor

equilibrium. Which of the following statements regarding this system is/are correct once

equilibrium is established?

1.

The rate of condensation is equal to the rate of evaporation.

2.

The fraction of molecules with enough energy to escape the liquid surface

depends on the liquid surface area.

3.

The vapor pressure is independent of the temperature.

A)

1 only

B)

2 only

C)

3 only

D)

1 and 2

E)

1, 2, and 3

10. If more ice is added to an ice-water mixture at equilibrium,

A)

the temperature will increase somewhat.

B)

the vapor pressure of the water will decrease.

C)

the temperature will decrease somewhat.

D)

the vapor pressure of the water will rise.

E)

the vapor pressure of the water will remain constant.

11. Which of the following involves a change in temperature during the phase transition?

A)

condensation of water

B)

fusion of ethanol

C)

vaporization of water

D)

all of the above

E)

none of the above

12. The boiling point of a liquid is

A)

always the temperature at which the vapor pressure equals 760 mmHg (1 atm).

B)

always the temperature at which the liquid phase of a substance is in equilibrium

with the vapor phase.

C)

always the temperature at which the vapor pressure equals the pressure exerted on

the liquid.

D)

always equal to the vapor pressure of the liquid at a given temperature.

E)

independent of the pressure exerted on the liquid.

13. Which one of the following liquids would you expect to have the highest vapor pressure at

room temperature? (all boiling points are normal boiling points)

A)

n-pentane, b.p. = 36.1°C

B)

methanol, b.p. = 65.0°C

C)

carbon tetrachloride, b.p. = 76.7°C

D)

acetic acid, b.p. = 118°C

E)

mercury, b.p. = 357°C

14. In which of the following processes will energy be evolved as heat?

A)

crystallization

B)

melting

C)

sublimation

D)

vaporization

E)

none of these

Test Bank General Chemistry, 10th edition 5

15. Which of the following phase changes are endothermic?

A)

vaporization

B)

freezing

C)

liquifaction

D)

crystallization

E)

condensation

16. The enthalpy of fusion of sodium is 2.60 kJ/mol. How many grams of sodium can be melted

by adding 81.7 kJ of energy to the metal at its melting point?

A)

7.22 102

g

B)

9.24 g

C)

3.55 g

D)

31.4 g

E)

1.50 103

g

17. Assume 12,500 J of energy is added to 2.0 moles (36 grams) of H2O as an ice sample at

0°C. The molar heat of fusion is 6.02 kJ/mol. The specific heat of liquid water is 4.18 J/g

°C. The molar heat of vaporization is 40.6 kJ/mol. The resulting sample contains which of

the following?

A)

water and water vapor

B)

ice and water

C)

only water

D)

only water vapor

E)

only ice

18. How much heat is released at constant pressure if a 14.0-L tank containing 56.0 atm of

hydrogen sulfide gas condenses at its boiling point of -60.0oC? The enthalpy of

vaporization of hydrogen sulfide is 18.7 kJ/mol at -60.0oC. (R = 0.0821 L • atm/(K • mol))

A)

1.17  102 J

B)

2.98  106 J

C)

4.17  102 J

D)

1.87  104 J

E)

8.38  105 J

19. What is the value of q when 8.21 g of water vaporizes at 373 K? The enthalpy of

condensation of water at 373 K is –40.7 kJ/mol.

A)

–334 kJ

B)

–18.5 kJ

C)

18.5 kJ

D)

334 kJ

E)

0.202 kJ

20. The vapor pressure of a liquid increases with increasing temperature. Which of the

following statements best explains this relationship?

A)

All the molecules have greater kinetic energies.

B)

The number of gaseous molecules above the liquid remains constant, but these

molecules have greater average kinetic energy.

C)

The faster-moving molecules in the liquid exert a greater pressure.

D)

The intermolecular forces between the molecules decrease at higher temperatures.

E)

The average kinetic energy of molecules is greater; thus more molecules can enter

the gaseous state.

21. The vapor pressure of a given liquid will increase if

A)

the liquid is moved to a container in which its surface is very much larger.

B)

the volume of the liquid is increased.

C)

the temperature is increased.

D)

the volume of the vapor phase is increased.

E)

a more volatile liquid is added to the given liquid.

Test Bank General Chemistry, 10th edition 7

22. A particular compound has an enthalpy of vaporization of 28300 J/mol. At 281 K it has a

vapor pressure of 101 mmHg. What is its vapor pressure at 301 K? (R = 8.31 J/(K· mol))

A)

98.8 mmHg

B)

123 mmHg

C)

45.2 mmHg

D)

226 mmHg

E)

103 mmHg

23. A liquid has an enthalpy of vaporization of 30.8 kJ/mol. At 275 K it has a vapor pressure of

117 mmHg. What is the normal boiling point of this liquid? (R = 8.31 J/(K· mol))

A)

293 K

B)

319 K

C)

275 K

D)

259 K

E)

241 K

24. In a certain mountain range, water boils at 94°C. What is the atmospheric pressure under

these conditions? The enthalpy of vaporization of water at 100°C is 40.7 kJ/mol.

(R = 8.31 J/(K · mol))

A)

1760 mmHg

B)

324 mmHg

C)

613 mmHg

D)

942 mmHg

E)

329 mmHg

25. For a particular liquid, raising its temperature from 319 K to 337 K causes its vapor pressure

to double. What is the enthalpy of vaporization of this liquid? (R = 8.31 J/(K · mol))

A)

34.4 kJ/mol

B)

320 kJ/mol

C)

2.01 kJ/mol

D)

228 kJ/mol

E)

104 kJ/mol

Test Bank General Chemistry, 10th edition 8

26. Knowing that Hvap for water is 40.7 kJ/mol, calculate Pvap of water at 37°C.

A)

52.7 torr

B)

25.4 torr

C)

18.7 torr

D)

12.4 torr

E)

6.90 torr

27. What is the enthalpy of vaporization of a compound that has a vapor pressure of 131 mmHg

at 211 K and 2.23 mmHg at 177 K? (R = 8.31 J/(K· mol))

A)

996 kJ/mol

B)

1.15 kJ/mol

C)

3.31 kJ/mol

D)

37.2 kJ/mol

E)

368 kJ/mol

28. In the accompanying phase diagram, a liquid can be present at combinations of temperature

and pressure corresponding to points

A)

A, C, G, and D.

B)

A, C, D, and F.

C)

A, B, C, and G.

D)

A and C only.

E)

G, C, D, and E.

Test Bank General Chemistry, 10th edition 9

29. Which of the following statements concerning the accompanying phase diagram is false?

A)

The solid is more dense than the liquid.

B)

Point C is the critical point of the substance.

C)

Point A is the triple point of the substance.

D)

The normal boiling point is above the triple point.

E)

The curve AD divides the solid region from the gas region.

30. Given the accompanying phase diagram, under what conditions will liquid be found in

equilibrium with either solid or gas?

A)

Anywhere along curve AB.

B)

Anywhere along curve AC.

C)

Anywhere along curve AD.

D)

Anywhere along curve AB and AC.

E)

Anywhere along curve AB and AD.

31. Choose the correct statement about the diagram below.

A)

The diagram shows the triple point above 1 atm pressure.

B)

The diagram is qualitatively correct for water.

C)

The diagram shows that the melting point of the solid increases with increasing

pressure.

D)

The diagram could represent the phase diagram of CO2.

E)

None of the above statements is correct.

32. From a consideration of the phase diagram below, a change from point M to point N

corresponds to

A)

sublimation.

B)

liquefaction.

C)

evaporation.

D)

condensation.

E)

freezing.

33. The triple point of iodine is at 90 torr and 115°C. This means that liquid I2

A)

cannot have a vapor pressure less than 90 torr.

B)

is more dense than I2(s).

C)

cannot exist at 1 atmosphere pressure.

D)

cannot exist above 115°C.

E)

can exist at pressure of 10 torr.

34. The critical point of CCl4 is 283°C and 45 atm pressure. Liquid CCl4 has a vapor pressure of

10.0 atm at 178°C. Which of the following statements must be true?

A)

Vapor and liquid can only be in equilibrium at one temperature—the normal

boiling point.

B)

Liquid CCl4 can exist at temperatures greater than 283°C if the pressure is greater

than 45 atm.

C)

Liquid and solid can only be in equilibrium at one temperature—the freezing point.

D)

The triple point of CCl4 must be less than 178°C.

E)

The normal boiling point of CCl4 must be greater than 178°C.

35. Below is a phase diagram for a substance.

What is the name for point X on the diagram?

A)

boiling point

B)

normal boiling point

C)

triple point

D)

melting point

E)

critical point

36. Below is a phase diagram for a substance.

Which line represents the melting-point curve of the substance?

A)

R-X

B)

S-X

C)

X-Z

D)

S-Z

E)

M-N

37. Below is a phase diagram for a substance.

Which line represents the vapor-pressure curve of the substance?

A)

S-Z

B)

X-Z

C)

S-X

D)

M-N

E)

R-X

38. If the liquid of a pure substance has a lower density than the solid, what is the effect on the

pressure-temperature phase diagram?

A)

The vapor-pressure curve arches upward.

B)

The normal melting point is above room temperature.

C)

The melting-point curve has a negative slope.

D)

The vapor-pressure curve arches downward.

E)

The melting-point curve has a positive slope.

39. Below is a phase diagram for a substance.

What is the name for point Z on the diagram?

A)

normal boiling point.

B)

critical point.

C)

melting point.

D)

boiling point.

E)

triple point.

40. Which explanation best describes surface tension?

A)

Molecules at the surface of a liquid experience a net force towards the liquid’s

interior.

B)

Molecules at the edges of a liquid adhere to the surface of the liquid’s container.

C)

Molecules of a liquid tend to form a concave meniscus.

D)

Molecules of a liquid tend to resist flow.

E)

Molecules of a liquid have a very low vapor pressure.

41. If the diameter of a spherical water droplet is 100.0 m, how much energy is required to

increase the diameter of the water droplet by 3.0 m? The surface tension of water is

1.0  10-3 J/m2.

A)

3.1  10–11 J

B)

1.9  10–12 J

C)

2.8  10–14 J

D)

7.7  10–12 J

E)

3.3  10–11 J

42. Which is the best reason for why water in a glass capillary has a concave meniscus, while

mercury in a glass capillary has a convex meniscus?

A)

Mercury has a greater dispersion force than water.

B)

The water is attracted more strongly to the glass than the mercury is attracted to the

glass.

C)

The mercury is attracted more strongly to the glass than the water is attracted to the

glass.

D)

Water is a molecular compound while mercury is a metallic element.

E)

Water has a greater dispersion force than mercury.

43. Which of the following forces is/are responsible for capillary action, a property of liquids?

1.

attractive forces between the liquid and the capillary material

2.

surface tension of the liquid

3.

viscosity of the liquid

A)

1

B)

2

C)

3

D)

1 and 2

E)

1, 2, and 3

44. Which of the following concerning surface tension and viscosity is/are correct?

1.

A molecule at the surface of a liquid experiences a net attractive force toward

the interior of the liquid.

2.

The surface tension of a liquid is unaffected by substances dissolved in the

liquid.

3.

The viscosity of a liquid is determined in part by the strength of

intermolecular forces.

A)

1 only

B)

2 only

C)

3 only

D)

1 and 2

E)

1 and 3

45. The measure of the resistance to flow of a liquid is

A)

London forces.

B)

van der Waals forces.

C)

viscosity.

D)

vapor pressure.

E)

surface tension.

46. In which of the following substances are intermolecular forces of attraction absent?

A)

HF(l)

B)

CCl4(l)

C)

NaCl(l)

D)

H2O(l)

E)

N2(l)

47. Which one of the following decreases as the strength of the attractive intermolecular forces

increases?

A)

The normal boiling temperature.

B)

The vapor pressure of a liquid.

C)

The extent of deviations from the ideal gas law.

D)

The heat of vaporization.

E)

The sublimation temperature of a solid.

48. Which of the following compounds has the highest normal boiling point?

A)

CH3CH2CH2CH3

B)

CH3Cl

C)

CH3CH2OH

D)

CH3OCH3

E)

CH3CH2CH3

49. Which of the following compounds has the highest vapor pressure at 25°C?

A)

CH3CH2OH

B)

CH3CH2CH2CH3

C)

CH3OCH3

D)

CH3CH2CH3

E)

CH3CH2CH2Cl

50. Which of the following pure substances has the lowest normal boiling point?

A)

H2S

B)

NH3

C)

H2O

D)

H2Te

E)

H2Se

51. Methane (CH4) is able to be liquefied at low temperatures due to which intermolecular

force?

A)

ionic bonding

B)

covalent bonding

C)

hydrogen bonding

D)

dipole–dipole

E)

London dispersion

52. Which compound has the lowest standard enthalpy of vaporization at 25°C?

A)

C6H14

B)

C8H16

C)

C5H12

D)

C8H18

E)

C7H16

53. Which of the following indicates the existence of strong intermolecular forces of attraction

in a liquid?

A)

a very low critical temperature

B)

a very low boiling point

C)

a very low vapor pressure

D)

a very low viscosity

E)

a very low enthalpy of vaporization

54. Which of the following compounds has the lowest normal boiling point?

A)

CH3CH2CH2NH2

B)

CH3CH2CH2F

C)

CH3CH2CH2OH

D)

CH3CH2COOH

E)

CH3CH(OH)CH3

55. Which of the following compounds is expected to have the lowest vapor pressure?

A)

CH3OCH3

B)

CH3CH2F

C)

CH3CH2OH

D)

CH3CH2CH2CH3

E)

CH3CH2CH3

56. Which of the following pure substances has the highest normal boiling point?

A)

HI

B)

HCl

C)

HF

D)

H2S

E)

HBr

57. Why does hydrogen fluoride have an unusually high normal boiling point compared to the

other hydrogen halides?

A)

The H-F bond in hydrogen fluoride is very strong.

B)

Hydrogen fluoride has very strong London dispersion forces.

C)

Hydrogen fluoride is capable of forming hydrogen bonds.

D)

Hydrogen fluoride is ionic.

E)

Hydrogen fluoride is covalent.

58. Which of the following pure substances has the lowest vapor pressure at 25°C?

A)

SbH3

B)

NH3

C)

PH3

D)

AsH3

E)

H2O

59. Which of the following pure substances has the highest vapor pressure at room temperature?

A)

Si3H8

B)

Si2H6

C)

Si2Cl6

D)

Si4H10

E)

SiH4

60. Which of the following pure substances has the highest standard enthalpy of vaporization at

25°C?

A)

H2O

B)

NH3

C)

PH3

D)

AsH3

E)

SbH3

61. At 25°C, the vapor pressure of diethyl ether, (CH3CH2)2O, is higher than the vapor pressure

of its isomer n-butanol, CH3CH2CH2CH2OH, because

A)

diethyl ether has a higher density than n-butanol.

B)

diethyl ether has weaker intermolecular forces than n-butanol.

C)

diethyl ether has a lower critical temperature than n-butanol.

D)

diethyl ether has a higher surface tension than n-butanol.

E)

diethyl ether has weaker intramolecular forces than n-butanol.

62. Which of the following pure substances has an unusually high normal boiling point?

A)

CH3OCH3

B)

CH3SH

C)

HCl

D)

CH3NH2

E)

CH3Cl

63. Rank the following molecules in order of increasing normal boiling point: CH3CH2OH,

CH3CH2CH2OH, CH3CH2OCH3.

A)

lowest CH3CH2CH2OH, CH3CH2OCH3, CH3CH2OH highest.

B)

lowest CH3CH2OH, CH3CH2OCH3, CH3CH2CH2OH highest.

C)

lowest CH3CH2CH2OH, CH3CH2OH, CH3CH2OCH3 highest.

D)

lowest CH3CH2OCH3, CH3CH2OH, CH3CH2CH2OH highest.

E)

lowest CH3CH2OCH3, CH3CH2CH2OH, CH3CH2OH highest.