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Problem 0.41
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 31a
Determine the number of atoms per unit cell for each metal.
(a) Polonium
Problem 31b
Determine the number of atoms per unit cell for each metal.
(b) Tungsten
Problem 31c
Determine the number of atoms per unit cell for each metal.
(c) Nickel
Problem 35
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 36
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 39
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 40
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 44a
Identify each solid as molecular, ionic, or atomic. a. Ru(s)
Problem 44b
Identify each solid as molecular, ionic, or atomic. b. H2O(s)
Problem 44d
Identify each solid as molecular, ionic, or atomic. d. Xe(s)
Problem 46
Which solid has the highest melting point? Why? C(s, diamond), Kr(s), NaCl(s), H2O(s)
Problem 47c
Which solid in each pair has the higher melting point and why? c. Kr(s) or Xe(s)
Problem 47d
Which solid in each pair has the higher melting point and why? d. NaCl(s) or CaO(s)
Problem 48d
Which solid in each pair has the higher melting point and why? d. H2O(s) or H2S(s)
Problem 50
An oxide of rhenium crystallizes with the unit cell shown here (rhenium=gray; oxygen=red). What is the formula of the oxide?
Problem 54
Identify the structure of each of the two unit cells shown in Problem 52 as the rock salt structure, zinc blende structure, fluorite structure, antifluorite structure, or none of these.
Problem 57a
Classify each of the following as a component of a silicate ceramic, an oxide ceramic, or a nonoxide ceramic. a. B4C
Problem 57b
Classify each of the following as a component of a silicate ceramic, an oxide ceramic, or a nonoxide ceramic. b. Mg2SiO4
Problem 57c
Classify each of the following as a component of a silicate ceramic, an oxide ceramic, or a nonoxide ceramic. c. MoSi2
Problem 63
Which solid would you expect to have little or no band gap? a. Cu(s) b. Si(s) c. As(s)
Problem 64
Which solid would you expect to have the largest band gap? a. As(s) b. Sb(s) c. Bi(s)
Problem 65
How many molecular orbitals are present in the conduction band of a sodium crystal with a mass of 3.67 g?
Problem 67
A substance has a band gap of 5.8 eV at 273 K. Is this substance best classified as an insulator, a semiconductor, or a metal?
Problem 70b
Indicate if each solid forms an n-type or a p-type semiconductor. b. germanium doped with gallium
Problem 71
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 73
Teflon is an addition polymer formed from the monomer shown here. Draw the structure of the polymer.
Problem 74
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 78
Polyacrylonitrile (PAN) is an addition polymer with the struc- ture shown here. Draw the structure of the monomer.
