Deck 12: Intermolecular Forces: Liquids and Solids

Question 1

The process in which a gas is transformed into a solid is called solidification.

Answer 1

False

Question 2

The phenomenon of supercooling refers to the existence of a metastable liquid at a temperature below that of its sublimation point.

Answer 2

False

Question 3

H₂NCH₂CH₂NH₂ probably has a higher boiling point at 1.00 atm pressure than CH₃CH₂CH₂NH₂.

Answer 3

True

Question 4

Van der Waals forces are a type of London force.

Question 5

Below are given the Lewis structures of five molecules. Which one displays the MOST hydrogen bonding?

A)
B)
C)
D)
E)

Question 6

The heat of deposition equals the negative of the heat of sublimation.

Question 7

Which of the following statements concerning molecules in the liquid state is true?

A) Cohesive forces are not important.
B) The molecules contract to fit the size of the container.
C) The molecules have no motion.
D) The molecules are in a patterned (oriented) arrangement.
E) The molecules are mobile and relatively close together.

Question 8

CH₄ probably has a lower boiling point at 1 atm than SnH₄.

Question 9

If one compares compound A, composed of nonpolar molecules, with compound B, composed of polar molecules, and both molecules have the same molecular formula, then it is true that:

A) both compounds have the same boiling point
B) A boils at a lower temperature than B
C) B will not boil
D) B boils at a lower temperature than A
E) we have to know the structural formula to determine the differences in boiling points of A and B

Question 10

All sides are equal in length and all angles are right angles. There is an atom at each corner and one in the center. This is a simple cubic cell.

Question 11

Below are given the Lewis structures of five molecules. Which one displays the LEAST hydrogen bonding?

A)
B)
C)
D)
E)

Question 12

A liquid will "wet" a surface if:

A) the liquid has a lesser density than the surface
B) the forces between the liquid molecules are weak
C) the liquid has a low vapor pressure
D) the forces between the molecules and the surface are greater than the forces between the molecules of the liquid
E) The liquid has low viscosity and the surface is smooth

Question 13

All sides are equal in length and all angles are right angles. There is an atom at each corner and one at the center of each side. This is a face-centered cubic cell.

Question 14

Surface tension is thought to be due to:

A) surface area trying to increase
B) air absorbed on the surface
C) solute concentrated on the surface
D) surface molecules having lower energy than bulk molecules
E) surface molecules having higher energy than molecules in the bulk

Question 15

Which probably has the lowest boiling point at 1.0 atm pressure?

A) PbH4
B) SnH4
C) SiH4
D) GeH4
E) CH4

Question 16

Which probably has the highest boiling point at 1.00 atm pressure?

A) H2NCH2CH2NH2
B) CH3CH2CH2NH2
C) (CH3)2CHNH2
D) CH3CH2NHCH3
E) (CH3)3N

Question 17

Surface tension of a liquid is the work or energy required to increase the surface area of a liquid

Question 18

Which of the following compounds has the highest boiling point?

A) NH3
B) H2O
C) HF
D) CH4
E) HBr

Question 19

The property of a liquid that measures its resistance to flow is called resistivity.

Question 20

Which probably has the lowest boiling point at 1.0 atm pressure?

A) C2H6
B) C4H10
C) C6H14
D) C3H8
E) C5H12

Question 21

According to the phase diagram given, which of the following statements is wrong?

A) At the temperature and pressure of point 1, substance W exists as a three-phase equilibrium system.
B) At the temperature of point 2, a pressure of 500 torr is sufficient to liquify gaseous W.
C) If the W(l) = W(g) system is maintained at the temperature of point 3 while pressure is decreased, more W will vaporize.
D) If liquid W is maintained at the pressure of point 4 while the temperature is increased to 80°C, the liquid will vaporize.
E) The existence of liquid W at -40°C and 500 torr represents the metastable condition of "supercooling."

Question 22

According to the phase diagram given, which of the following is INCORRECT?

A) At the temperature and pressure of point 1, substance U exists as a three-phase equilibrium system.
B) At the temperature and pressure of point 2, substance U exists as a one-phase gaseous system.
C) At the temperature and pressure of point 3, substance U exists as a two-phase system.
D) If the U(s)⇔ U(l) system is maintained at the temperature of point 4 while pressure is decreased steadily to about 300 torr, more U will freeze.
E) There are no conditions of temperature and pressure under which solid U will vaporize without melting first.

Question 23

A passage of substance directly from the vapor to the solid state is known as:

A) deposition
B) decomposition
C) sublimation
D) solidification
E) fusion

Question 24

When a liquid is in dynamic equilibrium with its vapor at a given temperature, the following conditions could exist: I) There is no transfer of molecules between liquid and vapor.
II) The vapor pressure has a unique value.
III) The opposing processes, (liquid to vapor) and (vapor to liquid), proceed at equal rates.
IV) The concentration of vapor is dependent on time.
Which of the above choices are applicable?

A) I
B) II and III
C) I, II, and III
D) II and IV
E) II, III and IV

Question 25

When a liquid is in equilibrium with its vapor in a closed container:

A) the rate at which molecules from the liquid phase enter the gas phase exactly equals the rate at which molecules from the gas phase pass into the liquid phase
B) a change in temperature will not change the pressure in the container
C) the amount of gas in the container must exactly equal the amount of liquid
D) molecules cannot go from the liquid phase to the gas phase because the amount of liquid in the container is constant
E) the vapor will gradually change back to the liquid state, that is, no vapor will be left

Question 26

The enthalpy of fusion is:

A) The quantity of heat required to melt a solid
B) The quantity of heat released when a solid melts
C) The quantity of heat when two elements are fused together to produce binary compound
D) The quantity of heat required to fuse two atomic nuclei
E) The quantity of heat released when an organic compound burns in an atmosphere of pure oxygen

Question 27

According to the phase diagram given, which of the following statements is INCORRECT?

A) At the temperature and pressure of point 1, W exists as a three-phase equilibrium system.
B) At the temperature of point 2, a pressure of 500 torr will cause W to liquefy.
C) If the system is maintained at the temperature of point 3 while pressure is decreased, more W will vaporize.
D) If W is maintained at the pressure of point 4 while the temperature is increased to 80°C, the liquid will vaporize.
E) The existence of liquid W at -40°C and 500 torr represents the metastable condition of "supercooling."

Question 28

Under which of the following conditions will vaporization best occur?

A) high mass, large surface area, high kinetic energy
B) weak forces between molecules, high kinetic energy, large surface area
C) high molecular energy, small surface area
D) low kinetic energy, strong molecular forces, large surface area
E) small surface area, low kinetic energy, low molecular mass

Question 29

Which of the following statements about viscosity are true: I) Viscosity is liquid's resistance to flow.
II) Viscosity decreases with a decrease in temperature.
III) Viscosity is not related to the forces between molecules in a liquid.
IV) Viscous liquids have low rate flows.

A) I) and IV)
B) I) and III)
C) I) and II)
D) II) and IV)
E) III and IV)

Question 30

The phenomenon in which a steel needle can, with proper care, be made to float on the surface of some water illustrates a property of liquids known as:

A) compressibility
B) polarizability
C) surface tension
D) triple point
E) viscosity

Question 31

A liquid has a normal boiling point of 78°C and its vapor pressure is 400 mmHg at 50°C. To compute the molar heat of vaporization, one needs:

A) the mole weight
B) all information has been provided
C) the vapor pressure at another temperature
D) the specific heat
E) molarity

Question 32

Which of the following keeps the rate of vaporization unchanged?

A) closing container lid
B) increasing forces between molecules
C) increasing mass of molecule
D) decreasing temperature
E) decreasing surface area

Question 33

Which of the following is true assuming point A has P = 180 mmHg, T = 50°C, point C has P = 275 mmHg, T = 200°C and points A, B, and C form a right triangle?

A) At point B, T = 50°C, P = 275 mmHg.
B) D is temperature, E is pressure.
C) D is pressure, E is volume.
D) At point B, T = 200°C, P = 275 mmHg.
E) B is a liquid.

Question 34

What is the difference between "normal boiling point" and "boiling point" of a liquid?

A) "Normal boiling point" is a boiling point of a liquid at normal (standard) pressure and temperature, while "boiling point" is measured at any other conditions of pressure and temperature.
B) "Normal boiling point" is a boiling point of 1 mol of a liquid with a surface of 1 m2, while "boiling point" is boiling temperature for any other amount of a substance.
C) "Normal boiling point" is a boiling point a liquid has at 1 atm of pressure; "boiling point" is a boiling temperature of a liquid at any other pressure.
D) "Normal boiling point" and "boiling point" are synonyms.
E) "Normal boiling point" refers to 1 g of substance; "boiling point" refers to any other amount of substance.

Question 35

Choose the INCORRECT statement.

A) In a network covalent solid, covalent bonds extend throughout the crystalline solid.
B) Diamond has sp3 hybridization.
C) Graphite has sp hybridization.
D) Fullarenes are a recently discovered allotropic form of carbons.
E) Nanotubes are an allotropic form of carbon.

Question 36

A liquid is in equilibrium with its vapor. If some of the vapor is allowed to escape, what is the immediate result?

A) The condensation rate decreases.
B) The vaporization rate increases.
C) The condensation rate increases.
D) The vaporization rate decreases.
E) The rates of condensation and vaporization are not effected.

Question 37

Vaporization occurs more readily with:

A) increased temperature, increased surface area, decreased volume
B) increased temperature, increased surface area, increased intramolecular forces
C) increased temperature, decreased surface area, decreased intermolecular forces
D) increased temperature, increased surface area, decreased intermolecular forces
E) increased temperature, decreased surface area, decreased intermolecular forces.

Question 38

According to the phase diagram given, which of the following statements is INCORRECT?

A) At the temperature and pressure of point 2, substance Z exists as a three-phase equilibrium system.
B) At the temperature and pressure of point 3, substance Z exists as a one-phase gaseous system.
C) If the Z(s) = Z(l) = Z(g) system is maintained at the temperature of point 2 while pressure is decreased, more Z will vaporize.
D) If liquid Z is maintained at the pressure of point 4 while the temperature is decreased to 30°C, the liquid will vaporize.
E) The existence of liquid Z at -50°C and 2 atm represents the metastable condition of "supercooling."

Question 39

The phenomenon of supercooling refers to the existence of a metastable:

A) liquid at a temperature below that of its critical point
B) liquid at a temperature below that of its sublimation point
C) liquid at a temperature below that of its freezing point
D) gas at a temperature below that of its critical point
E) two-phase liquid/solid mixture at the freezing point

Question 40

Which of the following describe the critical point of a liquid? I) the temperature and pressure at which a liquid's meniscus disappears
II) the point where the vapor pressure curve intersects the fusion temperature curve
III) the highest temperature and pressure at which a liquid can exist
IV) the highest temperature at which it is possible to obtain a liquid from its vapor by increasing pressure

A) I), II), III)
B) I), III), IV)
C) II), III)
D) II), III), IV)
E) I), IV)

Question 41

Three types of holes of the cubic closest packed structure are:

A) Trigonal, tetrahedral and octahedral
B) Tetrahedral, pyramidal and octahedral
C) Tetrahedral, bipyramidal and octahedral
D) Cubic,, tetrahedral, and octahedral
E) Tetragonal, tetrahedral and octahedral

Question 42

The property that causes water to have a concave meniscus but mercury to have a convex meniscus is ________.

A) heat of vaporization
B) sublimation
C) surface tension
D) vapor pressure
E) critical point

Question 43

The property of a liquid that measures its resistance to flow is called ________.

A) capillarity
B) polarizability
C) resistivity
D) viscosity
E) wetability

Question 44

Arrange the following compounds in order of increasing boiling point: HCl, HBr, HI.

A) HCl, HBr, HI
B) HBr, HI, HCl
C) HI, HBr, HCl
D) HCl, HI, HBr
E) HI, HCl, HBr

Question 45

Arrange in order by decreasing boiling point: CH3CH2OH, HOCH2CH2OH, C4H10

A) HOCH2CH2OH, CH3CH2OH, C4H10
B) C4H10, HOCH2CH2OH, CH3CH2OH
C) HOCH2CH2OH, C4H10, CH3CH2OH
D) C4H10, CH3CH2OH, HOCH2CH2OH
E) CH3CH2OH, C4H10, HOCH2CH2OH

Question 46

Which of the substances below would produce the hardest, most brittle crystals?

A) SiC
B) Xe
C) Cu
D) KNO3
E) H2O

Question 47

What is the maximum number of glycerol molecules [HOCH2CH(OH)CH2OH] that could form hydrogen bonds to a single molecule of the compound?

A) 1
B) 3
C) 5
D) 9
E) 14

Question 48

A compound of iron and sulfur crystallizes in a lattice pattern described as cubic closest packed sulfide ions, with iron ions in all octahedral sites. What is its empirical formula?

A) FeS
B) FeS2
C) Fe3S4
D) Fe2S
E) Fe2S3

Question 49

An atom at the corner of cubic unit cell is shared among:

A) six adjoining unit cells
B) four adjoining unit cells
C) eight adjoining unit cells
D) ten adjoining unit cells
E) twelve adjoining unit cells

Question 50

Which of the following compounds is the most viscous? CH3CH2OH, CH3CH2CH2CH3, HOCH2CH2OH, CH3OCH2CH3

A) CH3CH2OH
B) CH3CH2CH2CH3
C) CH3OCH2CH3
D) HOCH2CH2OH

Question 51

The enthalpy of vaporization at 298 K for diethylether (C4H10O) is 26.0 kJ/mol. How much heat would be required to vaporize 1.00 L of the ether at 298 K if its density is 0.714 g/L?

A) 440 J
B) 250 J
C) 186 J
D) 130 J
E) 74.1 J

Question 52

Which of the following ionic compounds should have the highest melting point?

A) NaI
B) MgO
C) NaCl
D) LiBr
E) CaS

Question 53

Arrange the following compounds in order of increasing boiling point: pentane (CH3CH2CH2CH2CH3), methyl butane (CH3CH(CH3)CH2CH3), neopentane (CH3C(CH3)3).

A) pentane, methyl butane, neopentane
B) neopentane, methyl butane, pentane
C) neopentane, pentane, methyl butane
D) pentane, neopentane, methyl butane
E) methyl butane, pentane, neopentane

Question 54

Arrange in order by decreasing boiling point: Cl2, I2, HI

A) I2, Cl2, HI
B) Cl2, I2, HI
C) Cl2, HI, I2
D) HI, Cl2, I2
E) HI, I2, Cl2

Question 55

There are no types of crystalline solids that are held together by:

A) dipole-dipole interactions
B) ionic attractions
C) hydrogen bonds
D) covalent bonds
E) pi bonds only

Question 56

Coordination number is:

A) The number of atoms per unit cell
B) The number of atoms in the corners of the unit cell
C) The number of atoms in contact with a given atom
D) The number of atoms in the holes of closest packed structures
E) The number of layers in close packed structures

Question 57

A crystal and its melt readily conduct electricity. The crystal also has a luster and is easily deformed. Thus, it is:

A) a covalent network crystal
B) an ionic crystal
C) a metallic crystal
D) a molecular crystal
E) a covalent crystal.

Question 58

Which combination of "type of solid" and specific example is INCORRECT?

A) ionic/"table salt"
B) metallic/copper wire
C) molecular/"dry ice"
D) network covalent/iodine
E) network covalent/silicon carbide

Question 59

Find a FALSE statement about X-rays.

A) diffracted by crystals
B) radiation of wavelength approximating 1 Angstrom
C) visible to the naked eye
D) used to determine the structure of molecules
E) produced using high-energy electrons

Question 60

The enthalpy of condensation is equal to, but opposite in sign from, the enthalpy of ________.

A) crystallization
B) formation
C) fusion
D) sublimation
E) vaporization

Question 61

A 0.90 g sample of liquid water was introduced into an evacuated 2.00 L flask, which was then sealed and heated to 37°C. What percentage, by mass, of the water remained as liquid? [Vapor pressure of water at 37°C = 48.2 torr.]

A) 10%
B) 18%
C) 82%
D) 90%
E) 0%

Question 62

Flask A has a volume of 0.50 L and contains 50 g of a volatile liquid. Flask B has a volume of 1.0 L and contains 25 g of the same liquid. Both flasks are stoppered and both are at 30°C. The ratio of the vapor pressure of the liquid in Flask A to that in Flask B is:

A) 4:1
B) 2:1
C) 1:1
D) 1:2
E) 1:4

Question 63

Arrange the following compounds in order of increasing boiling point: I) 1-propanol, CH3CH2CH2OH;
II) 1,2-propanediol, CH3CH(OH)CH2OH;
III) 1,2,3-propanetriol, (glycerol), HOCH2CH(OH)CH2OH.

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

Question 64

The heat of deposition equals the negative of the heat of ________.

A) fusion
B) condensation
C) sublimation
D) solidification
E) reposition

Question 65

Given the data below, determine the molar enthalpy change of vaporization of liquid Rb. Rb, P1 = 1.00 mmHg, t1 = 297°C, P2 = 400 mmHg, t2 = 620°C

A) 5.49 kJ/mol
B) 28.4 kJ/mol
C) 78.5 kJ/mol
D) 12.8 kJ/mol
E) 4.62 kJ/mol

Question 66

The normal boiling point of acetone is 56.2°C and the molar heat of vaporization is 32.0 kJ/mol. At what temperature will acetone boil under a pressure of 50.0 mmHg?

A) 156 °C
B) 6.0 °C
C) -6.0 °C
D) 40.7 °C
E) 73.6 °C

Question 67

How much heat would be released by the condensation of 5.40 g of steam at 100°C and the subsequent cooling of the water to 25°C? [ΔHvap = 40.7 kJ/mol at 100°C; Cp for H2O(l) is 4.18 J g-1 °C-1]

A) 12.2 kJ
B) 12.8 kJ
C) 13.9 kJ
D) 18.3 kJ
E) 23.7 kJ

Question 68

A liquid has a molar heat of vaporization of 22.7 kJ/mol. Its normal boiling point is 459K. What is the vapor pressure, in mmHg, at 70°C?

A) 102 mmHg
B) 7.48 mmHg
C) 56.8 mmHg
D) 742 mmHg
E) 580 mmHg

Question 69

The factor that has the largest effect on vapor pressure is ________.

A) liquid surface area
B) molecular dipole moment
C) presence of H bonding
D) liquid mole weight
E) volume available for vapor

Question 70

What would be the appropriate equilibrium temperature of a system obtained by adding 25.0 g of ice at 0°C to 250.0 mL of "hot" (80°C) coffee, assuming that the heat capacity and density of the coffee are the same as for pure water (4.18 J g-1 °C-1 and 0.997 g mL-1), and also assuming negligible heat transfer with the surroundings? [For water, ΔHfusion = 6.02 kJ/mol.]

A) 33°C
B) 40°C
C) 65°C
D) 73°C
E) 79°C

Question 71

Liquid and vapor phases of a substance become indistinguishable at the ________.

A) triple point
B) normal point
C) permanent point
D) critical point
E) absolute point

Question 72

The maximum temperature at which a gas can be liquefied is just below the ________.

A) boiling temperature
B) critical temperature
C) melting temperature
D) normal temperature
E) superheating temperature

Question 73

Given the data below, determine the normal boiling point of COCl2. P1 = 100 mmHg, t1 = -35.6°C, ΔHvap = 27.4 kJ/mol

A) 278°C
B) -65.1°C
C) -36.4°C
D) 5.0°C
E) -5.0°C

Question 74

Arrange the following compounds in order of increasing viscosity: I) 1-propanol, CH3CH2CH2OH;
II) 1,2-propanediol, CH3CH(OH)CH2OH;
III) 1,2,3-propanetriol, (glycerol), HOCH2CH(OH)CH2OH.

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

Question 75

Given the data below, determine the normal boiling point of liquid Rb. P1 = 400 mmHg, t1 = 620°C, ΔHvap = 78.5 kJ/mol

A) 374°C
B) 920°C
C) 647°C
D) 951°C
E) 678°C

Question 76

The relationship between the vapor pressure of a liquid and temperature can be expressed by the Clausius-Clapeyron equation: Log[P2/P1] = [ΔHvap/R] × [1/T1 - 1/T2]
Ethanol (C2H5OH) has a normal boiling point of 78.3°C and, with ΔHvap = 39.3 kJ/mol. What is the vapor pressure of ethanol at 50.0°C?

A) 118 torr
B) 234 torr
C) 354 torr
D) 485 torr
E) 670 torr

Question 77

A substance has a heat of fusion of 61.5 kJ/mol and a heat of deposition of -167.4 kJ/mol. What is the heat of sublimation in kJ/mol?

A) -61.5 kJ/mol
B) 61.5 - 167.4 kJ/mol
C) 61.5 + 167.4 kJ/mol
D) 167.4 - 61.5 kJ/mol
E) 167.4 kJ/mol

Question 78

When the vapor pressure of a liquid equals atmospheric pressure, the temperature of the liquid equals ________.

A) 100°C
B) the boiling point
C) the normal boiling point
D) the vaporization point
E) the sublimation point

Question 79

The temperature at which the vapor pressure of a liquid equals the external pressure is called the ________.

A) boiling point
B) critical point
C) melting point
D) sublimation point
E) thermal point

Question 80

Given the data below, determine the molar enthalpy change of vaporization of COCl2. COCl2, P1 = 40 mmHg, t1 = -50.3°C, P2 = 100 mmHg, t2 = -35.6°C

A) 0.518 kJ/mol
B) 27.4 kJ/mol
C) 4.32 kJ/mol
D) 0.928 kJ/mol
E) 0.112 kJ/mol