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Problem 0.37
Plonium crystallizes with a simple cubic structure. It has a density of 9.3 g/cm3, a radius of 167 pm, and a molar mass of 209 g/mol. Use these data to calculate Avogadro's number (the number of atoms in one mole).
Problem 27
An X-ray beam with l = 154 pm incident on the surface of a crystal produced a maximum reflection at an angle of u = 28.3°. Assuming n = 1, calculate the separation between layers of atoms in the crystal.
Problem 29a
Determine the number of atoms per unit cell for each metal.
(a) Polonium
Problem 29b
Determine the number of atoms per unit cell for each metal.
(b) Tungsten
Problem 29c
Determine the number of atoms per unit cell for each metal.
(c) Nickel
Problem 33
Platinum crystallizes with the face-centered cubic unit cell. The radius of a platinum atom is 139 pm. Calculate the edge length of the unit cell and the density of platinum in g/cm3 .
Problem 34
Molybdenum crystallizes with the body-centered unit cell. The radius of a molybdenum atom is 136 pm. Calculate the edge length of the unit cell and the density of molybdenum
Problem 35
Rhodium has a density of 12.41 g/cm3 and crystallizes with the face-centered cubic unit cell. Calculate the radius of a rhodium atom.
Problem 36
Barium has a density of 3.59 g/cm3 and crystallizes with the body-centered cubic unit cell. Calculate the radius of a barium atom.
Problem 40a
Identify each solid as molecular, ionic, or atomic. a. CaCl2(s)
Problem 40b
Identify each solid as molecular, ionic, or atomic. b. CO2(s)
Problem 40d
Identify each solid as molecular, ionic, or atomic. d. I2(s)
Problem 42
Which solid has the highest melting point? Why? C(s, diamond), Kr(s), NaCl(s), H2O(s)
Problem 43c
Which solid in each pair has the higher melting point and why? c. Kr(s) or Xe(s)
Problem 43d
Which solid in each pair has the higher melting point and why? d. NaCl(s) or CaO(s)
Problem 44d
Which solid in each pair has the higher melting point and why? d. H2O(s) or H2S(s)
Problem 46
An oxide of rhenium crystallizes with the unit cell shown here (rhenium=gray; oxygen=red). What is the formula of the oxide?
Problem 50
Identify the structure of each of the two unit cells shown in Problem 48 as the rock salt structure, zinc blende structure, fluorite structure, antifluorite structure, or none of these.
Problem 53a
Classify each of the following as a component of a silicate ceramic, an oxide ceramic, or a nonoxide ceramic. a. B4C
Problem 53b
Classify each of the following as a component of a silicate ceramic, an oxide ceramic, or a nonoxide ceramic. b. Mg2SiO4
Problem 53c
Classify each of the following as a component of a silicate ceramic, an oxide ceramic, or a nonoxide ceramic. c. MoSi2
Problem 59
Which solid would you expect to have little or no band gap? a. Zn(s) b. Si(s) c. As(s)
Problem 60
Which solid would you expect to have the largest band gap? a. As(s) b. Sb(s) c. Bi(s)
Problem 61
How many molecular orbitals are present in the conduction band of a lithium crystal with a mass of 11.2 g?
Problem 63
A substance has a band gap of 6.9 eV at 273 K. Is this substance best classified as an insulator, a semiconductor, or a metal?
Problem 66b
Indicate if each solid forms an n-type or a p-type semiconductor. b. germanium doped with antimony
Problem 67
Does a photon of red light with a frequency of 4.29 * 1014 Hz have sufficient energy to promote an electron from the valence band to the conduction band in a sample of silicon (the band gap in silicon is 1.11 eV)?
Problem 69
Teflon is an addition polymer formed from the monomer shown here. Draw the structure of the polymer.
Problem 70
Saran, the polymer used to make saran wrap, is an addition polymer formed from two monomers—vinylidene chloride and vinyl chloride. Draw the structure of the polymer. (Hint: The monomers alternate.)
Problem 74
Polyacrylonitrile (PAN) is an addition polymer with the struc- ture shown here. Draw the structure of the monomer.
