Deck 12: Intermolecular Forces and Liquids and Solids

Question 1

Which of the following would be expected to have the highest vapor pressure at room temperature?

A)ethanol, bp = 78°C
B)methanol, bp = 65°C
C)water, bp = 100°C
D)acetone, bp = 56°C

Answer 1

acetone, bp = 56°C

Question 2

For which of the following species are the intermolecular interactions entirely due to dispersion forces?

A)C₂H₆
B)CH₃OCH₃
C)NO₂
D)H₂S
E)CaNO₃

Answer 2

C₂H₆

Question 3

Which of the following substances should have the lowest boiling point?

A)CBr₄
B)CBr₃F
C)CBr₂F₂
D)CBrF₃
E)CF₄

Answer 3

CF₄

Question 4

Which one of the following substances is expected to have the highest boiling point?

A)HBr
B)HCl
C)HF
D)HI

Question 5

Which one of the following substances should exhibit hydrogen bonding in the liquid state?

A)PH₃
B)H₂
C)H₂S
D)CH₄
E)NH₃

Question 6

Which one of the following substances is expected to have the lowest melting point?

A)BrI
B)CsI
C)LiI
D)NaI
E)RbI

Question 7

Which of the following substances should have the highest boiling point?

A)CH₄
B)Cl₂
C)Kr
D)CH₃Cl
E)N₂

Question 8

Which of the following properties indicates the presence of strong intermolecular forces in a liquid?

A)a low heat of vaporization
B)a low critical temperature
C)a low vapor pressure
D)a low boiling point
E)None of the above.

Question 9

Which of the following liquids would have the lowest viscosity at 25°C?

A)
B)
C)
D)
E)

Question 10

Helium atoms do not combine to form He₂ molecules, yet He atoms do attract one another weakly through

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

Question 11

Atoms share electrons.

A)1 and 4
B)1 and 3
C)2 and 3
D)2 and 4
E)3 and 4

Question 12

The molecular property related to the ease with which the electron density in a neutral atom or molecule can be distorted is called

A)a dipole moment.
B)polarizability.
C)a dispersion force.
D)surface tension.
E)a van der Waals force.

Question 13

Which one of the following substances is expected to have the highest boiling point?

A)Br₂
B)Cl₂
C)F₂
D)I₂

Question 14

Which of the following liquids would have the highest viscosity at 25°C?

A)CH₃OCH₃
B)CH₂Cl₂
C)C₂H₅OH
D)CH₃Br
E)HOCH₂CH₂OH

Question 15

Which of the following characteristics indicates the presence of weak intermolecular forces in a liquid?

A)a low heat of vaporization
B)a high critical temperature
C)a low vapor pressure
D)a high boiling point
E)None of the above.

Question 16

Which one of the following substances will have both dispersion forces and dipole-dipole forces?

A)HCl
B)BCl₃
C)Br₂
D)H₂
E)CO₂

Question 17

Each of the following substances is a liquid at -50°C. Place these liquids in order of increasing vapor pressure: dimethyl ether (CH₃OCH₃), propane (C₃H₈), and ethanol (CH₃CH₂OH)_.

A)ethanol < propane < dimethyl ether
B)ethanol < dimethyl ether < propane
C)propane < dimethyl ether < ethanol
D)dimethyl ether < ethanol < propane
E)propane < ethanol < dimethyl ether

Question 18

For which of the following species are the dispersion forces strongest?

A)C₄H₁₀
B)C₅H₁₂
C)C₆H₁₄
D)C₇H₁₆
E)C₈H₁₈

Question 19

Which of the following would be expected to have the lowest vapor pressure at room temperature?

A)ethanol, bp = 78°C
B)methanol, bp = 65°C
C)water, bp = 100°C
D)acetone, bp = 56°C

Question 20

Which of the following properties indicates the presence of weak intermolecular forces in a liquid?

A)a high heat of vaporization
B)a high critical temperature
C)a high vapor pressure
D)a high boiling point
E)None of the above.

Question 21

Given the following liquids and their boiling points, which has the highest vapor pressure at its normal boiling point?

A)ethanol, bp = 78°C
B)methanol, bp = 65°C
C)water, bp = 100°C
D)benzene, bp = 80°C
E)The vapor pressure of each of the liquids at its normal boiling point would be the same.

Question 22

Which of the following atoms does not participate in hydrogen bonding?

A)S
B)O
C)F
D)N

Question 23

The number of atoms in a body-centered cubic unit cell is

A)1.
B)2.
C)3.
D)4.
E)8.

Question 24

Arrange the following in order of increasing boiling point: RbCl, CH₃Cl, CH₃OH, CH₄.

A)CH₃OH < CH₃Cl < RbCl < CH₄
B)CH₃OH < CH₄ < CH₃Cl < RbCl
C)RbCl < CH₃Cl < CH₃OH < CH₄
D)CH₄ < CH₃OH < CH₃Cl < RbCl
E)CH₄ < CH₃Cl < CH₃OH < RbCl

Question 25

The number of atoms in a face-centered cubic unit cell is

A)1.
B)2.
C)3.
D)4.
E)8.

Question 26

Which one of the following crystallizes in a metallic lattice?

A)C
B)NaMnO₄
C)K
D)LiClO₄
E)K₂Cr₂O₇

Question 27

Which of the following substances would have the highest critical temperature?

A)CH₃Cl
B)C₂H₆
C)F₂
D)H₂
E)CO₂

Question 28

Which one of the following substances crystallizes as a covalent crystal?

A)CaO
B)SiO₂
C)CO₂
D)Pb
E)KMnO₄

Question 29

Which one of the following is an example of a covalent network solid?

A)SiO₂
B)K
C)I₂
D)CaCl₂
E)None of these.

Question 30

Which property of water allows a razor blade to float on it without sinking?

A)viscosity
B)surface tension
C)density
D)specific heat
E)triple point

Question 31

Which one of the following substances crystallizes as a molecular solid?

A)KI
B)SiO₂
C)Sn
D)CH₃OH
E)Al₂(SO₄)₃

Question 32

An example of a covalent network solid is

A)diamond.
B)potassium.
C)iodine.
D)sodium chloride.
E)None of these.

Question 33

Each of the following substances is a gas at 25°C and 1 atmosphere pressure. Which one will liquefy most easily when compressed at a constant temperature?

A)F₂
B)H₂
C)HF
D)SiH₄
E)Ar

Question 34

Which of the responses includes all of the following that can form hydrogen bonds with water molecules? (1)Na⁺ (2)CH₃COOH (3)C₂H₆ (4)CH₃NH₂

A)(1)and (2)
B)(1)and (3)
C)(2)and (3)
D)(2)and (4)
E)(3)and (4)

Question 35

The structural form of the element Ge closely resembles the structure of

A)C (diamond).
B)N (diatomic).
C)As (tetrahedral).
D)S (S₈ ring).
E)Kr (monatomic).

Question 36

Krypton has a higher melting point than argon because of its

A)hydrogen bonding.
B)stronger dispersion forces.
C)permanent dipole moment.
D)ionic bonds.
E)greater ionization energy.

Question 37

Which of the following is not true with regard to water?

A)Water has a high heat capacity.
B)Water has an unusually high boiling point.
C)Water can form hydrogen bonds.
D)Ice is more dense than liquid water.
E)Water is a polar molecule.

Question 38

Which one of the following substances should exhibit hydrogen bonding in the liquid state?

A)SiH₄
B)H₂
C)H₂S
D)CH₄
E)CH₃NH₂

Question 39

Choose the response that lists the member of each of the following pairs that has the higher boiling point. (I)H₂O or KI (II)HF or HI (III)Cl₂ or Br₂

A)H₂O, HF, and Cl₂
B)KI, HF, and Br₂
C)KI, HI, and Br₂
D)H₂O, HI, and Cl₂
E)KI, HF, and Cl₂

Question 40

Which one of the following substances should exhibit hydrogen bonding in the liquid state?

A)PH₃
B)He
C)H₂S
D)CH₄
E)CH₃OH

Question 41

MgO has the same crystal structure as NaCl, face-centered cubic. How many oxide ions surround each Mg²⁺ ion as nearest neighbors?

A)4
B)6
C)8
D)10
E)12

Question 42

Potassium bromide, KBr, crystallizes like NaCl in a face-centered lattice. The ionic radii of K⁺ and Br^- ions are 133 pm and 195 pm, respectively. Assuming that all Br^- ions are positioned in the face and corners of the unit cell, while the K⁺ ions are positioned along the edge alternating between anions, calculate the length of a unit cell edge.

A)230 pm
B)328 pm
C)523 pm
D)656 pm
E)780 pm

Question 43

Acetic acid has a heat of fusion of 10.8 kJ/mol and a heat of vaporization of 24.3 kJ/mol. What is the expected value for the heat of sublimation of acetic acid?

A)35.1 kJ/mol
B)-13.5 kJ/mol
C)+13.5 kJ/mol
D)-35.1 kJ/mol
E)Not enough information is given to answer the question.

Question 44

The mineral manganosite, manganese(II)oxide, crystallizes in the rock salt structure (the face-centered structure adopted by NaCl)with a density of 5.365 g/cm³. Find the unit cell edge length of manganosite.

A)444.5 pm
B)352.8 pm
C)280.0 pm
D)368.2 pm
E)417.9 pm

Question 45

Use the graph of vapor pressure to determine the normal boiling point of CHCl₃.

A)19°C
B)52°C
C)60°C
D)64°C
E)70°C

Question 46

The specific heat of liquid ethanol, C₂H₅OH(l), is 2.46 J/g·°C and the heat of vaporization is 39.3 kJ/mol. The boiling point of ethanol is 78.3 °C. What amount of enthalpy is required to heat 50.0 g of liquid ethanol from 23.0 °C to ethanol vapor at 78.3 °C?

A)42.7 kJ
B)49.5 kJ
C)179 kJ
D)1970 kJ
E)6840 kJ

Question 47

Use the graph of vapor pressure to determine the normal boiling point of O₂.

A)92 K
B)90 K
C)88 K
D)84 K
E)O₂ doesn't boil because it is always a gas.

Question 48

The number of nearest neighbors (atoms that make contact)around each atom in a face-centered cubic lattice of a metal is

A)2.
B)4.
C)6.
D)8.
E)12.

Question 49

Silver metal crystallizes in a face-centered cubic lattice with L as the length of one edge of the unit cube. The center-to-center distance between nearest silver atoms is

A)L/2.
B)
C)2L.
D)
E)None of the above.

Question 50

Potassium crystallizes in a body-centered cubic lattice. How many atoms are there per unit cell?

A)1
B)2
C)4
D)6
E)8

Question 51

Calculate the amount of heat needed to melt 2.00 kg of iron at its melting point (1,809 K), given that $\Delta$ H_fus = 13.80 kJ/mol.

A)494 kJ
B)27,600 kJ
C)27.6 kJ
D)27,600 J
E)25,000 kJ

Question 52

The zincblende structure of ZnS has the relatively large sulfide ions arranged at the lattice points of a face-centered cubic structure. The edge length of this cubic unit cell is 540.9 pm. Determine the density of zincblende.

A)3.081 g/cm³
B)1.023 g/cm³
C)4.091 g/cm³
D)2.046 g/cm³
E)2.032 g/cm³

Question 53

Platinum has a face-centered cubic crystal structure and a density of 21.5 g/cm³. What is the radius of the platinum atom?

A)69 pm
B)98 pm
C)139 pm
D)196 pm
E)277 pm

Question 54

Which of the following is not an endothermic process?

A)melting of a solid
B)vaporization
C)raising the temperature of a gas
D)condensation of water vapor
E)sublimation of dry ice

Question 55

The triple point of iodine is at 0.12 atm and 115°C. Thus, liquid I₂

A)is more dense than I₂ (s).
B)cannot exist above 115°C.
C)is liquid at room temperature.
D)cannot have a vapor pressure less than 91 torr.

Question 56

Calculate the amount of heat that must be absorbed by 10.0 g of ice at -20°C to convert it to liquid water at 60.0°C. Given: specific heat (ice)= 2.1 J/g·°C; specific heat (water)= 4.18 J/g·°C; $\Delta$ H_fus = 6.0 kJ/mol.

A)420 J
B)2,900 J
C)6,300 J
D)63 kJ
E)7.5 J

Question 57

A liquid boils when its

A)vapor pressure is exactly 1 atmosphere.
B)vapor pressure is equal to, or greater than, the external pressure pushing on it.
C)temperature is equal to 273 K (standard temperature).
D)temperature is greater than room temperature.

Question 58

The heat capacity of liquid water is 4.18 J/g·°C and the heat of vaporization is 40.7 kJ/mol. How many kilojoules of heat must be provided to convert 1.00 g of liquid water at 67°C into 1.00 g of steam at 100°C?

A)22.7 kJ
B)40.8 kJ
C)2.2 kJ
D)2,400 J
E)40.8 J

Question 59

Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.0 g/cm³ at 27°C. Calculate the atomic radius of Pd.

A)138 pm
B)1.95 * 10^-8 nm
C)1.95 * 10^-8 cm
D)154 pm
E)0.109 nm

Question 60

Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density of V?

A)5.96 g/cm³
B)2.98 g/cm³
C)2.98 * 10^-6 g/cm³
D)5.96 * 10^-30 g/cm³
E)11.9 g/cm³

Question 61

Find the temperature at which water boils on a day in the mountains when the barometric pressure is 593 mmHg. (Given: the heat of vaporization of water is 40.79 kJ/mol)

A)93.1°C
B)117°C
C)41.5°C
D)97.0°C
E)68.1°C

Question 62

What mass of water would need to evaporate from your skin in order to dissipate 1.7 * 10⁵ J of heat from your body? H₂O(l) $\rarr$ H₂O(g) $\Delta$ H_vap = 40.7 kJ/mol

A)7.52 * 10⁴ g
B)418 g
C)75.2 g
D)58.4 g
E)6.92 * 10⁶ g

Question 63

Find the temperature at which ethanol boils on a day in the mountains when the barometric pressure is 547 mmHg. (Given: The heat of vaporization of ethanol is 39.3 kJ/mol; the normal boiling point of ethanol is 78.3°C.)

A)76.5°C
B)69.9°C
C)10.0°C
D)77.9°C
E)74.6°C

Question 64

Identify the dominant (strongest)type of intermolecular force present in H₂S(g).

Question 65

How much energy (heat)is required to convert 52.0 g of ice at -10.0°C to steam at 100°C? specific heat of ice: 2.09 J/g·°C $\Delta$ H_fus = 6.02 kJ/mol
Specific heat of water: 4.18 J/g·°C $\Delta$ H_vap = 40.7 kJ/mol
Specific heat of steam: 1.84 J/g·°C

A)2,570 kJ
B)1,086 kJ
C)157.8 kJ
D)40.2 kJ
E)22,957 kJ

Question 66

Solid iodine has a vapor pressure of 1.0 mmHg at 39°C. How many moles of iodine will sublime into a 500. mL flask at this temperature? If the volume of the flask is doubled at constant temperature, what will happen to the equilibrium vapor pressure of I₂? (Assume some solid I₂ is always present in the container.)

A)2.1 * 10^-4 mol; vapor pressure increases
B)2.0 * 10^-2 mol; vapor pressure increases
C)2.6 * 10^-5 mol; no change in vapor pressure
D)2.1 * 10^-4 mol; no change in vapor pressure
E)2.6* 10^-5 mol; vapor pressure decreases

Question 67

The normal boiling point of bromine is 58.8°C. Given that the vapor pressure of bromine is 75.0 torr at 2.5°C, calculate the molar enthalpy of vaporization of bromine.

A)3.76 kJ/mol
B)31.3 kJ/mol
C)2.90 kJ/mol
D)3.57 kJ/mol
E)29.7 kJ/mol

Question 68

The vapor pressure of a liquid in a closed container depends upon

A)the amount of liquid.
B)the surface area of the liquid.
C)the volume of the container.
D)the temperature.
E)None of the above.

Question 69

Use the following data to determine the molar heat of vaporization of chlorine. T (°C)-84.5 -71.2 -47.3
P (mmHg)40.0 100.0 400.0

A)34,700 J
B)21,900 J
C)317 J
D)712 J
E)9.99 kJ

Question 70

The molar heats of sublimation and fusion of iodine are 62.3 kJ/mol and15.3 kJ/mol, respectively. Calculate the molar heat of vaporization of liquid iodine.

A)77.6 kJ/mol
B)47.0 kJ/mol
C)-47.0 kJ/mol
D)-77.6 kJ/mol
E)4.07 kJ/mol

Question 71

Which one of the following elements would have the lowest melting point?

A)Kr
B)Br₂
C)S₈
D)Ca
E)K

Question 72

Which of the following gases would have the highest critical temperature?

A)CH₄
B)O₂
C)CO₂
D)NH₃
E)Ne

Question 73

Identify the dominant (strongest)type of intermolecular force present in RbCl(s).

Question 74

The vapor pressure of ethanol is 400 mmHg at 63.5°C. Its molar heat of vaporization is 39.3 kJ/mol. What is vapor pressure of ethanol, in mmHg, at 34.9°C?

A)1,510 mmHg
B)100 mmHg
C)200 mmHg
D)0.0099 mmHg
E)4.61 mmHg

Question 75

The molar enthalpy of vaporization of carbon disulfide is 26.74 kJ/mol, and its normal boiling point is 46°C. What is the vapor pressure of CS₂ at 0°C?

A)447 torr
B)4160 torr
C)313 torr
D)139 torr
E)5.47 torr

Question 76

Based on the phase diagram shown below, how will the melting point of the substance change if the pressure is increased above 1 atm?

A)The melting point will decrease.
B)The melting point will remain the same.
C)The melting point will increase.
D)The substance will not melt at pressures of 1 atm and above; instead, the solid sublimes to form the gas phase.

Question 77

The normal boiling point of methanol (CH₃OH)is 64.6°C. Given that the vapor pressure of methanol is 75.0 torr at 15.2°C, calculate the molar enthalpy of vaporization of methanol.

A)0.383 kJ/mol
B)3.00 kJ/mol
C)38.0 kJ/mol
D)27.5 kJ/mol
E)74.7 kJ/mol

Question 78

The molar enthalpy of vaporization of hexane (C₆H₁₄)is 28.9 kJ/mol, and its normal boiling point is 68.73°C. What is the vapor pressure of hexane at 25°C?

A)171 torr
B)4.44 torr
C)117 torr
D)3370 torr
E)759 torr

Question 79

The molar enthalpy of vaporization of boron tribromide is 30.5 kJ/mol, and its normal boiling point is 91°C. What is the vapor pressure of BBr₃ at 20°C?

A)11.5 torr
B)311 torr
C)5.31 torr
D)143 torr
E)66.1 torr

Question 80

Octane is a liquid component of gasoline. Given the following vapor pressures of octane at various temperatures, estimate the boiling point of octane in Leadville, Colorado, where the atmospheric pressure is 496 mmHg. 400 mmHg @ 104°C, 500 mmHg @ 111°C, 600 mmHg @ 117°C,
700 mmHg @ 122°C, 760 mmHg @ 125°C

A)125°C
B)120°C
C)115°C
D)110°C
E)105°C