Deck 16: Liquids and Solids

Question 1

Identify the major attractive force in CaF₂.

A) ionic bonding
B) London dispersion forces
C) hydrogen bonding
D) dipole-dipole interactions
E) none of these

Answer 1

ionic bonding

Question 2

Identify the major attractive force in H₂S.

A) London dispersion forces
B) hydrogen bonding
C) ionic bonding
D) dipole-dipole interactions
E) none of these

Answer 2

dipole-dipole interactions

Question 3

Which of the following chemical species has the highest boiling point?

A) Ne
B) CH₄
C) Li₂O
D) O₂
E) NF₃

Answer 3

Li₂O

Question 4

Which of the following compounds has the lowest boiling point?

A) CH₄
B) C₂H₆
C) C₅H₁₂
D) C₃H₈
E) C₄H₁₀

Question 5

Which of the following is the correct order of boiling points for NaNO₃, C₂H₅OH, C₂H₆, and Ne?

A) Ne < C₂H₆ < NaNO₃ < C₂H₅OH
B) Ne < C₂H₆ < C₂H₅OH < NaNO₃
C) Ne < C₂H₅OH < C₂H₆ < NaNO₃
D) NaNO₃ < C₂H₅OH < C₂H₆ < Ne
E) C₂H₆ < Ne < C₂H₅OH < NaNO₃

Question 6

Identify the major attractive force in HF.

A) dipole-dipole interactions
B) ionic bonding
C) hydrogen bonding
D) London dispersion forces
E) none of these

Question 7

The resistance of a liquid to an increase in its surface area is called

A) capillary action.
B) viscosity.
C) surface tension.
D) vapor pressure
E) none of these

Question 8

Which of the following chemical species has the highest boiling point?

A) H₂
B) He
C) CH₄
D) NO
E) N₂

Question 9

Which of the following is most likely to be a gas at room temperature?

A) H₂O
B) C₈H₁₈
C) K₂S
D) O₂
E) MgF₂

Question 10

Which substance involves no intermolecular forces except London dispersion forces?

A) NaF
B) N₂
C) HF
D) H₂S
E) K

Question 11

Which statement regarding water is true?

A) Liquid water is less dense than solid water.
B) Only covalent bonds are broken when ice melts.
C) Hydrogen bonds are stronger than covalent bonds.
D) Energy must be given off in order to break down the crystal lattice of ice to a liquid.
E) All of these statements are false.

Question 12

Identify the major attractive force in Ne.

A) ionic bonding
B) dipole-dipole interactions
C) London dispersion forces
D) hydrogen bonding
E) none of these

Question 13

Which of the following should have the highest boiling point?

A) K₂S
B) NH₃
C) HF
D) C₂H₅OH
E) O₂

Question 14

Which one of the following is the strongest intermolecular force experienced by noble gases?

A) polar covalent bonds
B) hydrogen bonding
C) London dispersion forces
D) ionic bonding
E) dipole-dipole interactions

Question 15

Properties of liquids lie (closer to/further from) properties of a solid than to (or from) properties of a gas.

A) closer to
B) further from

Question 16

On the basis of your knowledge of bonding in liquids and solids, which of the following substances has the highest melting temperature?

A) CH₄
B) H₂O
C) Br₂
D) SO₂
E) KBr

Question 17

Molecular complexity leads to lower viscosity.

Question 18

The elements of Group 5A, the nitrogen family, form compounds with hydrogen that have the boiling points listed below. SbH₃ -17°C, AsH₃ -55°C, PH₃ -87°C, NH₃ -33°C
The first three elements illustrate a trend where the boiling point decreases as the mass decreases; however, ammonia (NH₃) does not follow the trend because of

A) ionic bonding.
B) hydrogen bonding.
C) metallic bonding.
D) dipole-dipole attraction.
E) London dispersion forces.

Question 19

Identify the major attractive force in Cl₂.

A) London dispersion forces
B) hydrogen bonding
C) ionic bonding
D) dipole-dipole interactions
E) none of these

Question 20

Which intermolecular force is the strongest?

A) polar covalent bonds
B) ionic bonding
C) London dispersion forces
D) dipole-dipole interactions
E) hydrogen bonding

Question 21

Which of the following statements is(are) false?
I.The hexagonal closest-packed structure is ABAB....
II.A body-centered cubic unit cell has four atoms per unit cell.
III.For unit cells having the same edge length, a simple cubic structure would have a smaller density than a body-centered cube.
IV.Atoms in a solid consisting of only one element would have six nearest neighbors if the crystal structure was a simple cubic array.

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

Question 22

The molar volume of a certain form of solid lead is 18 cm³/mol. Assuming cubic closest-packed structure, determine the following.

-The volume of a single cell

A) 1.20 * 10⁶ pm³
B) 1.20 *10⁸ pm³
C) 1.20 *10⁴ pm³
D) 1.20 *10² pm³
E) none of these

Question 23

The molar volume of a certain form of solid lead is 18 cm³/mol. Assuming cubic closest-packed structure, determine the following.
The radius of a Pb atom

A) 1740 pm
B) 17.4 pm
C) 174 pm
D) 1.74 pm
E) none of these

Question 24

Elemental magnesium crystallizes in a face-centered cubic lattice. The density of magnesium is 1.738 g/cm³. The unit cell length is 4.80 * 10² pm. What is the atomic radius of Mg?

A) 340 pm
B) 215 pm
C) 242 pm
D) 126 pm
E) 170 pm

Question 25

Pure rubidium crystallizes in a body-centered cubic lattice; the edge length of the unit cell is 562 pm. What is the density of rubidium in grams per cubic centimeter?

A)
B)
C)
D)
E)

Question 26

If equal, rigid spheres are arranged in a simple cubic lattice in the usual way (that is, in such a way that they touch each other), what fraction of the corresponding solid will be empty space? [The volume of a sphere is (4/3) $\pi$ r³, with $\pi$ = 3.14.]

A) 0.52
B) 0.32
C) 0.68
D) 0.48
E) none of these

Question 27

In cubic closest-packed solids, what percentage of space is occupied by the spheres?

A) 68.0%
B) 74.0%
C) 52.4%
D) 43.8%
E) none of these

Question 28

Chromium metal crystallizes as a body-centered cubic lattice. If the atomic radius of Cr is 1.25 angstroms, what is the density of Cr metal in grams per cubic centimeter?

A) 2.76 g/cm³
B) 5.52 g/cm³
C) 7.18 g/cm³
D) 3.59 g/cm³
E) 7.81 g/cm³

Question 29

Aluminum metal crystallizes in a face-centered cubic structure. What is the relationship between the radius of an Al atom (r) and the length of an edge of the unit cell (E)?

A)
B)
C) r = 2E
D) r = 4E
E) r = E/2

Question 30

Which of the following is the smallest hole in a closest-packed lattice of spheres?

A) trigonal
B) cubic
C) tetrahedral
D) octahedral
E) none of these

Question 31

A metal crystallizes in a body-centered unit cell with an edge length of 2.18 * 10² pm. Assume the atoms in the cell touch along the cube diagonal. What will be the percentage of empty volume in the unit cell?

A) 68.0%
B) 75.5%
C) 0.00%
D) 32.0%
E) 26.0%

Question 32

A sample of Co crystallizes in the hexagonal closest-packed (hcp) structure. Each atom in a layer is surrounded by and touches 6 other Co atoms. If the distance between Co atom centers within each layer is 2.0 *10² pm, what is the distance between centers of nearest neighbors in adjacent layers?

A) 1.5 * 10² pm
B) 4.0 *10² pm
C) 2.3 * 10² pm
D) 2.0* 10² pm
E) none of these

Question 33

Mn crystallizes in the same cubic unit cell as Cu. Assuming that the radius of Mn is 5.6% larger than the radius of Cu and that the density of copper is 8.96 g/cm³, calculate the density of Mn.

A) 7.67 g/cm³
B) 8.48 g/cm³
C) 9.46 g/cm³
D) 6.58 g/cm³
E) 9.12 g/cm³

Question 34

What is the net number of face-centered atoms contained in a face-centered cubic unit cell?

A) 6
B) 1
C) 3
D) 4
E) none of these

Question 35

Which substance can be described as cations bonded together by mobile electrons?

A) S₈(s)
B) Ag(s)
C) Kr(l)
D) HCl(l)
E) KCl(s)

Question 36

The unit cell in this two-dimensional crystal contains __________ Xs and __________ Os.

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

Question 37

Which one of the following statements about solid Cu (face-centered cubic unit cell) is incorrect?

A) There are two atoms per unit cell.
B) The solid has a cubic closest-packed structure.
C) It will conduct electricity.
D) The number of atoms surrounding each Cu atom is 12.
E) The length of a face diagonal is four times the Cu radius.

Question 38

The molar volume of a certain form of solid lead is 18 cm³/mol. Assuming cubic closest-packed structure, determine the following.
The number of Pb atoms per unit cell

A) 3
B) 4
C) 10
D) 12
E) 14

Question 39

What is the radius of the largest sphere that can be placed at the center of a face-centered cubic unit cell of a cubic closest-packed array of spheres if the spheres have diameters of 4.00 *10² pm?

A) 2.0* 10² pm
B) 41.5 pm
C) 83.0 pm
D) 4.0 * 10² pm
E) none of these

Question 40

A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. What is the diameter of the metal atom?

A) 408 pm
B) 353 pm
C) 577 pm
D) 204 pm
E) 288 pm

Question 41

Brass is an example of

A) a superconductor.
B) an interstitial alloy.
C) a network solid.
D) a substitutional alloy.
E) none of these

Question 42

Which of the following statements is true about p-type silicon?

A) Electrons are the mobile charge carriers.
B) It is produced by doping Si with P or As.
C) It does not conduct electricity as well as pure Si.
D) All are true.
E) None is true.

Question 43

In the unit cell of sphalerite, Zn²⁺ ions occupy half the tetrahedral holes in a face-centered cubic lattice of S^2- ions. What is the number of formula units of ZnS in the unit cell?

A) 3
B) 5
C) 4
D) 1
E) 2

Question 44

Sodium oxide (Na₂O) crystallizes in a structure in which the O^2- ions are in a face-centered cubic lattice and the Na⁺ ions are in tetrahedral holes. What is the number of Na⁺ ions in the unit cell?

A) 8
B) 2
C) 4
D) 6
E) none of these

Question 45

A salt, MY, crystallizes in a body-centered cubic structure with a Y^- anion at each cube corner and an M⁺ cation at the cube center. Assuming that the Y^- anions touch each other and the M⁺ cation at the center, and that the radius of Y^- is 1.46 * 10² pm, what is the radius of M⁺?

A) 73.0 pm
B) 48.7 pm
C) 107 pm
D) 38.0 pm
E) 60.5 pm

Question 46

A certain solid substance that is very hard, has a high melting point, and is nonconducting unless melted is most likely to be

A) Cu
B) NO₂
C) NaCl
D) I₂
E) H₂S

Question 47

A p-type semiconductor

A) is made by doping host atoms with atoms having more valence electrons than the host.
B) has electrons that lie close in energy to the conduction bands.
C) is made by doping host atoms with atoms having fewer valence electrons than the host.
D) two of these
E) none of these

Question 48

Which of the following substances would you expect to have the lowest boiling point?

A) sodium nitrate, NaNO₃
B) copper
C) methane, CH₄
D) glycerine, C₃H₅(OH)₃
E) diamond

Question 49

A certain compound with a molar mass of 138.0 g/mol crystallizes with the sodium chloride (rock salt) structure. The length of an edge of the unit cell is 488 pm. What is the density of this compound?

A) 1.97 g/cm³
B) 1.88 g/cm³
C) 4.75 g/cm³
D) 7.89 g/cm³
E) 1.19 g/cm³

Question 50

Cs crystallizes in a body-centered cubic arrangement. Assuming that the dimensions of the unit cell for Cs and for CsCl are equivalent, determine the ratio of the density of Cs to the density of CsCl.

A) 1.58
B) 2.79
C) 1.00
D) 0.789
E) none of these

Question 51

The unit cell in a certain lattice consists of a cube formed by an anion at each corner, an anion in the center, and a cation at the center of each face. The unit cell contains a net

A) 2 anions and 3 cations.
B) 2 anions and 2 cations.
C) 5 anions and 3 cations.
D) 3 anions and 4 cations.
E) 5 anions and 6 cations.

Question 52

Which of the following statements is incorrect?

A) Ionic solids have high melting points.
B) The binding forces in a molecular solid include London dispersion forces.
C) Ionic solids are insulators.
D) Molecular solids have high melting points.
E) All of these statements are correct.

Question 53

Which of the compounds below is an example of a network solid?

A) NaCl(s)
B) S₈(s)
C) MgO(s)
D) SiO₂(s)
E) C₂₅H₅₂(s)

Question 54

Alkali halides commonly have either the sodium chloride structure or the cesium chloride structure. The molar mass of CsCl is 2.88 times the molar mass of NaCl, and the edge length of the unit cell for NaCl is 1.37 times the edge length of the CsCl unit cell. Determine the ratio of the density of CsCl to the density of NaCl.

A) 0.541
B) 0.984
C) 1.85
D) 1.02
E) 2.10

Question 55

A material is made from Al, Ga, and As. The mole fractions of these elements are 0.25, 0.26, and 0.49, respectively. This material would be

A) an insulator.
B) an n-type semiconductor.
C) a metallic conductor because Al is present.
D) a p-type semiconductor.
E) none of these

Question 56

Metallic copper crystallizes in a face-centered cubic lattice. The volume of the unit cell is 4.11 *10⁸ pm³. What is the density of copper metal?

A) 5.14 g/cm³
B) 373 g/cm³
C) 10.3 g/cm³
D) 2.57 g/cm³
E) 62.0 g/cm³

Question 57

Doping Se with As would produce a(n) __________ semiconductor with __________ conductivity compared to pure Se.

A) n-type, increased
B) p-type, increased
C) n-type, decreased
D) intrinsic, identical
E) p-type, decreased

Question 58

A crystal of NaCl is

A) hard, high-melting, and a good electrical conductor.
B) soft, low-melting, and a good electrical conductor.
C) hard, high-melting, and a poor electrical conductor.
D) soft, high-melting, and a poor electrical conductor.
E) soft, low-melting, and a poor electrical conductor.

Question 59

You are given a small bar of an unknown metal, X. You find the density of the metal to be 10.5 g/cm³. An X-ray diffraction experiment measures the edge of the unit cell as 409 pm. Assuming that the metal crystallizes in a face-centered cubic lattice, what is X most likely to be?

A) Ag
B) Pt
C) Rh
D) Pb
E) none of these

Question 60

A certain metal fluoride crystallizes in such a way that the fluoride ions occupy simple cubic lattice sites, while the metal atoms occupy the body centers of half the cubes. What is the formula for the metal fluoride?

A) MF
B) M₂F
C) MF₈
D) MF₂
E) none of these

Question 61

In which of the following processes is energy evolved as heat?

A) vaporization
B) crystallization
C) melting
D) sublimation
E) none of these

Question 62

What is the vapor pressure of water at 80°C?

A) 0.48 atm
B) 1.20 atm
C) 2.00 atm
D) 0.80 atm
E) 1.00 atm

Question 63

\(\Delta\H_vap for water is 40.7 kJ/mol. Calculate the boiling point of water at 0.500 atm.

A) 50.0°C
B) 81.3°C
C) 100.0°C
D) 98.6°C
E) none of these

Question 64

When 1.00 mol of a pure liquid is vaporized at a constant pressure of 1.00 atm and at its boiling point of 330.8 K, 31.86 kJ of energy (heat) is absorbed and the volume change is +25.32 L. What is $\Delta$ E for this process? (1 L-atm = 101.3 J)

A) 29.30 kJ
B) 34.42 kJ
C) -34.42 kJ
D) -2.53 * 10³ kJ
E) -29.30 kJ

Question 65

Shown below is a phase diagram for compound X. At 25°C and 1 atm, in what state will X exist?

A) gas/solid at equilibrium.
B) liquid.
C) gas/liquid at equilibrium.
D) solid.
E) gas.

Question 66

A liquid placed in a closed container will evaporate until equilibrium is reached. At equilibrium, which of the following statements is not true?

A) Liquid molecules are still evaporating.
B) The number of vapor molecules remains essentially constant.
C) The partial pressure exerted by the vapor molecules is called the vapor pressure of the liquid.
D) The boundary (meniscus) between the liquid and the vapor disappears.
E) All of these statements are true.

Question 67

The triple point of a substance is

A) the point at which the vapor pressure of the solid is 1 atm.
B) the point at which its solid, liquid, and vapor are all in equilibrium.
C) the point at which the liquid starts to condense as the temperature of the vapor is lowered.
D) the point at which the density of the solid and the liquid are equal.
E) none of these

Question 68

A sample consisting of CO₂(g) and CO₂(s) at equilibrium at -78°C and 1 atm pressure is heated to -30°C, and the pressure is increased to 8 atm. Based on the phase diagram below, what will happen?

A) At equilibrium, only CO₂(g) will be present.
B) The melting point of the CO₂(s) will decrease.
C) At equilibrium, CO₂(g) and CO₂(l) will be present.
D) All the CO₂ will be converted to CO₂(l).
E) none of these

Question 69

What is the vapor pressure of water at 100.0°C?

A) 85 torr
B) 175 torr
C) 760 torr
D) 1 torr
E) More information is needed.

Question 70

Below is a phase diagram for compound X. What is the normal boiling point of X is most likely to be?

A) 0° C
B) 73° C
C) 15° C
D) 47° C
E) 18° C

Question 71

Given below are the temperatures at which two different liquid compounds with the same empirical formula have a vapor pressure of 400 torr. Which of the following statements is false?

A) Increasing the temperature will increase the vapor pressure of both liquids.
B) Intermolecular attractive forces are stronger in (liquid) ethanol than in (liquid) dimethyl ether.
C) The normal boiling point of dimethyl ether will be higher than the normal boiling point of ethanol.
D) The reason why the temperature at which the vapor pressure is 400 torr is higher for ethanol (than for dimethyl ether) is that there is strong hydrogen bonding in ethanol.
E) None of these statements is false.

Question 72

When 1.00 mol of a pure liquid is vaporized at a constant pressure of 1.06 atm and at its boiling point of 313.4 K, 30.00 kJ of energy (heat) is absorbed and the volume change is +25.80 L. What is $\Delta$ H for this process? (1 L-atm = 101.3 J)

A) -32.77 kJ
B) 32.77 kJ
C) 27.23 kJ
D) -27.23 kJ
E) 30.00 kJ

Question 73

Which of the following statements is true about the vapor pressures of methane (CH₄) and ammonia (NH₃)?

A) The vapor pressure of ammonia is less than the vapor pressure of methane because ammonia is nonpolar and methane is polar.
B) The vapor pressure of ammonia is greater than the vapor pressure of methane because ammonia is polar and methane is nonpolar.
C) The vapor pressure of methane is greater than the vapor pressure of methane because methane has more hydrogen bonding than ammonia.
D) The vapor pressure of ammonia is equal to the vapor pressure of methane.
E) None of these statements is true.

Question 74

The heat of vaporization of a certain refrigerant is 148 J/g. Calculate the number of kilograms of refrigerant that must be evaporated to freeze a tray of 16 one-ounce (1 oz = 28 g) ice cubes starting with the water at 15°C. Heat capacity (water) = 4.184 J/g °C
\(\Delta\H_fusion (water) = 333 J/g

A) 0.82 kg
B) 1.2 kg
C) 4.2 kg
D) 1.1 kg
E) 0.19 kg

Question 75

You are given the following boiling-point data: water, H₂O
100° C
Methanol, CH₃OH
64)96° C
Ethanol, CH₃CH₂OH
78)5° C
Diethyl ether, CH₃OH₂-O-CH₂CH₃
34)5° C
Ethylene glycol, HO-CH₂-CH₂-OH
198° C
Which one of these liquids would you expect to have the highest vapor pressure at room temperature?

A) diethyl ether, CH₃OH₂-O-CH₂CH₃
B) ethanol, CH₃CH₂OH
C) ethylene glycol, HO-CH₂-CH₂-OH
D) methanol, CH₃OH
E) water, H₂O

Question 76

Given the graph below, what is the boiling point of carbon tetrachloride at standard pressure?

A) The graph does not give this information.
B) 98°C
C) 77°C
D) 60°C
E) 34°C

Question 77

The normal boiling point of liquid X is less than that of Y, which is less than that of Z. Which of the following is the correct order of increasing vapor pressure of the three liquids at STP?

A) Z, Y, X
B) Y, Z, X
C) X, Z, Y
D) Y, X, Z
E) X, Y, Z

Question 78

Which of the following processes must exist in equilibrium with the condensation process when a measurement of vapor pressure is made?

A) evaporation
B) fusion
C) sublimation
D) boiling
E) none of these

Question 79

How much energy is needed to convert 64.6 grams of ice at 0.00°C to water at 55.2°C? Specific heat of ice = 2.10 J/(g°C)
Specific heat of water = 4.18 J/(g°C)
Heat of fusion = 333 J/g
Heat of vaporization = 2258 J/g

A) 60.1 kJ
B) 14.9 kJ
C) 161 kJ
D) 36.4 kJ
E) 6.59 kJ

Question 80

Knowing that $\Delta$ H_vap for water is 40.7 kJ/mol, calculate P_vap of water at 37°C.

A) 12.4 torr
B) 52.6 torr
C) 18.7 torr
D) 6.90 torr
E) 25.4 torr