Chapter 11 – Intermolecular Forces and Liquids and Solids
44. The number of atoms in a body-centered cubic unit cell is
45. The number of atoms in a face-centered cubic unit cell is
46. A face-centered cubic unit cell is the repeating unit in which type of crystal packing?
Chapter 11 – Intermolecular Forces and Liquids and Solids
47. The most space efficient arrangement of spheres is found in which type of unit cell?
48. The most space efficient arrangement of spheres is found in which type(s) of atom
arrangement?
I. hexagonal close-packed
II. cubic close-packed
III. simple cubic
IV. body-centered cubic
Chapter 11 – Intermolecular Forces and Liquids and Solids
49. In the following picture, each arrow represents a molecule or atom. Based on the arrangement in the solid state as
shown, which of the following best represents the unit cell?
Chapter 11 – Intermolecular Forces and Liquids and Solids
50. In the following picture, each arrow represents a molecule or atom. Based on the arrangement in the solid state as
shown, which of the following best represents the unit cell?
Chapter 11 – Intermolecular Forces and Liquids and Solids
51. The number of nearest neighbors (atoms that make contact) around each atom in a face-
centered cubic lattice of a metal is
52. Potassium crystallizes in a body-centered cubic lattice. How many atoms are there per unit
cell?
Chapter 11 – Intermolecular Forces and Liquids and Solids
53. BaCl2 crystallizes such that the Ba2+ ions are in a face-centered cubic arrangement and the
Cl– ions are in the holes of the lattice (fluorite structure). How many Cl– ions are present in
one unit cell of this crystal?
54. SrF2 crystallizes such that the Sr2+ ions are in a face-centered cubic arrangement and the F–
ions are in the holes of the lattice (fluorite structure). How many F– ions are present in one
unit cell of this crystal?
Chapter 11 – Intermolecular Forces and Liquids and Solids
55. Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.0 g/cm3 at 27C.
Calculate the atomic radius of Pd.
56. 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?
Chapter 11 – Intermolecular Forces and Liquids and Solids
57. 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.
58. Platinum has a face-centered cubic crystal structure and a density of 21.5 g/cm3. What is
the radius of the platinum atom?
Chapter 11 – Intermolecular Forces and Liquids and Solids
59. 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.
60. 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.
Chapter 11 – Intermolecular Forces and Liquids and Solids
61. MgO has the same crystal structure as NaCl, face-centered cubic. How many oxide ions
surround each Mg2+ ion as nearest neighbors?
62. The atomic planes in a graphite crystal are separated by 335 pm. At what angle would you
find the first-order (n = 1) diffraction of 0.154 nm X-rays from a graphite crystal?
Chapter 11 – Intermolecular Forces and Liquids and Solids
63. The triple point of iodine is at 0.12 atm and 115C. Thus, liquid I2
64. A liquid boils when its
Chapter 11 – Intermolecular Forces and Liquids and Solids
65.
Which of the following substances is expected to have the highest molar heat of vaporization (Hvap)?
66. 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
67C into 1.00 g of steam at 100C?
Chapter 11 – Intermolecular Forces and Liquids and Solids
67. 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?
Chapter 11 – Intermolecular Forces and Liquids and Solids
68.
Use the graph of vapor pressure to determine the normal boiling point of CHCl3.
Chapter 11 – Intermolecular Forces and Liquids and Solids
69. 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?
Chapter 11 – Intermolecular Forces and Liquids and Solids
70.
Use the graph of vapor pressure to determine the normal boiling point of O2.
Chapter 11 – Intermolecular Forces and Liquids and Solids
72. Which of the following phase changes is endothermic?
73. Which of the following phase changes is exothermic?
Chapter 11 – Intermolecular Forces and Liquids and Solids
74.
Calculate the amount of heat that must be absorbed by 10.0 g of ice at –20C to convert it to liquid water at 60.0C. Given:
specific heat (ice) = 2.1 J/g·C; specific heat (water) = 4.18 J/g·C; Hfus = 6.0 kJ/mol.
75.
Calculate the amount of heat needed to melt 2.00 kg of iron at its melting point (1,809 K), given that Hfus = 13.80 kJ/mol.
Chapter 11 – Intermolecular Forces and Liquids and Solids
76.
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) → H2O(g) Hvap = 40.7 kJ/mol
77.
How much energy (heat) is required to convert 52.0 g of ice at –10.0C to steam at 100C?
specific heat of ice:
2.09 J/g·C
specific heat of water:
4.18 J/g·C
specific heat of steam:
1.84 J/g·C
Chapter 11 – Intermolecular Forces and Liquids and Solids
78.
How much energy (heat) is required to convert 25.5 g of H2O(l) at 35.0C to H2O(g) at 115.0C?
specific heat of ice:
2.09 J/g·C
specific heat of water:
4.18 J/g·C
specific heat of steam:
1.84 J/g·C
79.
Which of the following constants is/are needed to calculate the amount of energy required to heat 30.5g of H2O(s) at –25.0C
to H2O(l) at 55.0C?
I. Hfus (H2O)
II. Hvap (H2O)
III. specific heat of H2O(s)
IV. specific heat of H2O(l)
V. specific heat of H2O(g)