Additional Practice for Ch 10 and 11
1. Which of the following solids has a crystal structure containing discrete (or
separate) molecules?
a. NaCl
b. CH4
c. graphite
d. diamond
e. SiO2
2. A solid that has a very high melting point, it is very hard and its liquid is nonconducting. The solid is
a. an ionic solid
b. a network solid
c. a metallic solid
d. an atomic solid
e. a molecular solid
3. Which of the following compounds would be expected to have the highest
melting point?
a. LiCl
b. CCl4
c. MgCl2
d. NCl3
e. OCl2
4. Which of the following compounds would be expected to have the highest
melting point?
a. LiCl
b. NaCl
c. MgCl2
d. BaCl2
e. BCl3
5. Which of the following substances is most likely to exist as a solid at room
temperature?
a. NF3
b. PF5
c. SF6
d. BF3
e. BaF2
6. Which of the following indicates very strong intermolecular forces of attraction in
a liquid? EXPLAIN
a.
b.
c.
d.
e.
a very low boiling point
a very low critical temperature
a very low heat of vaporization
a very low vapor pressure
a very low surface tension
7. All of the following indicate very strong intermolecular forces of attraction in a
liquid EXCEPT: EXPLAIN
a.
b.
c.
d.
e.
a very high boiling point
a very high vapor pressure
a very high critical temperature
a very high viscosity
a very high heat of vaporization
8. The compounds Br2 and ICl have almost identical molecular weights, yet ICl boils
at 97°C and Br2 boils at 59°C. The best explanation for the difference is
a.
b.
c.
d.
e.
ICl is an ionic compound and Br2 is covalent
ICl is a nonpolar compound and Br2 is polar
ICl has a longer bond than that in Br2
ICl has a measurable dipole moment and Br2 does not
ICl has a stronger bond than that in Br2
9. Which compound should have the highest vapor pressure at room temperature?
a. C4H10
b. C5H12
c. C6H14
d. C7H16
e. C8H18
10. Which of the following compounds would be expected to have the lowest boiling
point?
a. CH3CH2CH2F
b. CH3CH2CH2OH
c. CH3CHOHCH2
d. CH3CH2COOH
e. CH3CH2CH2NH2
11. Which of the following compounds shows and abnormal boiling point due to
hydrogen bonding?
a. CH3NH2
b. CH3OCH3
c. CH3SH
d. CH3Cl
e. HCl
12. Which of the following compounds is expected to have the highest boiling point?
a. CH3CH3
b. CH3CH2CH3
c. CH3OCH3
d. CH3CH2CH2Cl
e. CH3CH2CH2Br
13. Which compound should have the lowest vapor pressure at room temperature?
a. SiH4
b. Si2H6
c. Si2Cl6
d. Si3H8
e. Si4H10
14. Which of the following would be expected to have the highest heat of
vaporization?
a. H2O
b. NH3
c. PH3
d. AsH3
e. SbH3
15. Which of the following would be expected to have the highest heat of
vaporization?
a. CH3CH2CH3
b. CH2OCH3
c. CH3CHO
d. CH3CH2NH2
e. CH3CH2F
16. Which of the following has the lowest boiling point?
a. H2O
b. H2S
c. H2Se
d. H2Te
e. NH3
17. Which of the following compounds would be expected to have the highest
boiling point?
a. CH2CH2NH2
b. CH3CH2F
c. CH3OCH3
d. CH3CHO
e. CH3CH2CH3
18. Which of the following solutions would be expected to be the poorest conductor
of an electric current at room temperature?
a. CH3COOH
b. NaCl
c. MgCl2
19. Which of the following solutions would be expected to be the best conductor of
an electric current at room temperature?
a. sucrose
b. acetic acid
c. ammonium carbonate
d. sodium chloride
20. Which of the following solutes in aqueous solution would be expected to exhibit
the smallest freezing point lowering?
a. NaCl
b. MgCl2
c. Al2(SO4)3
21. Which of the following solutes dissolved in 1.0 kg of water would be expected to
boil at the highest temperature?
a. Acetic acid
b. sucrose
c. MgSO4
d. HCl
e. Ca(NO3)2
Essays
1. The boiling point of carbon tetrachloride (CCl4) is higher than that of chloroform
(CHCl3). Since chloroform is polar and carbon tetrachloride is not, consideration of
dipole-dipole forces would predict that chloroform would have the higher boiling
point. How can we account for the observed order of the boiling points?
2) Explain each of the following in terms of atomic and molecular structures and/or
intermolecular forces.
(a) Solid K conducts an electric current, whereas solid KNO3 does not.
(b) SbCl3 has a measurable dipole moment, whereas SbCl5 does not.
(c) The normal boiling point of CCl4 is 77 °C, whereas that of CBr4 is 190 °C.
(d) NaI(s) is very soluble in water whereas I2(s) has a solubility of only 0.03 gram
per 100 grams of water.