Chem1405 homework chap6
1. In which of the following phases of matter do the particles have virtually no
interaction with one another? (Section 6.1)
a. gas
b. liquid
c. solid
2. Which of the following statements about London forces is true? (Section 6.2)
a. London forces occur between polar bonds.
b. London forces are the strongest intermolecular force.
c. London forces are transient.
3.
a.
b.
c.
Which of the following statements about CCl2F2 is correct? (Section 6.2)
Although the bonds are polar, the molecule is nonpolar.
The bonds are polar and the molecule is polar.
The bonds are nonpolar and the molecule is nonpolar.
4. Which of the following examples shows the secondary forces in increasing strength?
(Sections 6.1-6.3)
a. London forces < dipole-dipole < hydrogen bond
b. hydrogen bond < dipole-dipole < London force
c. dipole-dipole < hydrogen bond < London force
5. Arrange the molecules H2O, CH4, and CH3F order of increasing boiling point.
(Section 6.4)
a. H2O < CH4 < CH3F
b. CH3F < CH4 < H2O
c. CH4 < CH3F < H2O
6. Which of the molecules, H2O or CCl4, would have a higher heat of vaporization?
(Sections 6.1-6.4)
a. H2O
b. CCl4
c. The two molecules would have similar heats of vaporization.
7. Which of the following statements about vapor pressure is NOT true? (Section 6.7)
a. The smaller the attractive forces between molecules, the greater the vapor pressure.
b. When the vapor pressure of a liquid is equal to the atmospheric pressure, a liquid will
boil.
c. The higher a liquid is above sea level, the greater the temperature required for
the liquid to boil.
8. In which type of crystal are the attractive forces between molecules the strongest?
(Section 6.9)
a. covalent
b. ionic
c. molecular
9.
Hint: Hydrogen bonds require an H covalently bonded to an O, N, or F. Answer c is the
only pair where this occurs in both compounds.
10.
Hint: Each of these molecules has only London Dispersion forces as intermolecular
forces. Molecules with higher molecular weight have the stronger London Dispersion
forces, therefore, C8H18 > C6H14 > C4H10> C3H8.
11.
Hint: (b) has the greater heat of vaporization because it can form hydrogen bonds
between molecules, whereas (a) cannot.
12.
a  c  b These are ordered by increasing strength of intermolecular forces, ionic >
hydrogen bond > London dispersion forces.
13.
Hint: Water molecules interact through both dipole–dipole forces and hydrogen bonds
while hexane can interact only by London forces. The secondary attractive forces
between water molecules are much stronger than those in hexane, and water will
consequently have a higher surface tension.
14.
Hint: H2S < H2O < KCl These are ordered by decreasing strength of secondary forces,
dipole-dipole < hydrogen bond < ionic forces.
15.
Hint: