176 ❯ STEP 4. Review the Knowledge You Need to Score High
- The approximate boiling points for hydrogen
compounds of some elements in the nitrogen
family are (SbH 3 – 15°C), (AsH 3 – 62°C),
(PH 3 – 87°C), and (NH 3 – 33°C). Which of
the following is the best explanation for the fact
that NH 3 does not follow the trend of the other
hydrogen compounds?
(A) NH 3 is the only one to exhibit hydrogen
bonding.
(B) NH 3 is the only one that is water soluble.
(C) NH 3 is the only one that is nearly ideal in the
gas phase.
(D) NH 3 is the only one that is a base. - Why is it possible to solidify argon at a suffi-
ciently low temperature?
(A) London dispersion forces are present.
(B) Covalent bonds form.
(C) Hydrogen bonds form.
(D) Metallic bonds form. - Which of the following best describes why dia-
mond is so hard?
(A) London dispersion forces are present.
(B) Covalent bonds are present.
(C) Hydrogen bonds are present.
(D) Metallic bonds are present. - A sample of a pure liquid is placed in an open
container and heated to the boiling point. Which
of the following may increase the boiling point of
the liquid?
(A) The moles of liquid are increased.
(B) The size of the container is increased.
(C) A vacuum is created over the liquid.
(D) The container is sealed. - The compounds 1-butanol, CH 3 CH 2 CH 2 CH 2 OH,
and diethyl ether, CH 3 CH 2 OCH 2 CH 3 , are iso-
mers (have the same chemical formula, C 4 H 10 O).
However, the surface tension of 1-butanol is
higher than that of diethyl ether. Which of the
following best explains why the surface tension
of 1-butanol is higher than that of diethyl ether?
(A) the higher density of 1-butanol
(B) the lower specific heat of 1-butanol
(C) the lack of hydrogen bonding in 1-butanol
(D) the presence of hydrogen bonding in 1-butanol
12. The compounds propanol, CH 3 CH 2 CH 2 OH,
ethylene glycol, HOCH 2 CH 2 OH, and butane,
CH 3 CH 2 CH 2 CH 3 , are all similar in size. Which
of the following most likely represents the relative
solubilities of these compounds in water?
(A) CH 3 CH 2 CH 2 OH < HOCH 2 CH 2 OH <
CH 3 CH 2 CH 2 CH 3
(B) CH 3 CH 2 CH 2 CH 3 < HOCH 2 CH 2 OH <
CH 3 CH 2 CH 2 OH
(C) CH 3 CH 2 CH 2 CH 3 < CH 3 CH 2 CH 2 OH <
HOCH 2 CH 2 OH
(D) CH 3 CH 2 CH 2 OH < CH 3 CH 2 CH 2 CH 3 <
HOCH 2 CH 2 OH
13. Each of the following compounds has a similar
structure, and the interionic distances are about
the same size. Which compound is expected to
have the highest lattice energy?
(A) LiCl
(B) MgO
(C) AlN
(D) NaF
14. The melting point of sodium fluoride, NaF, is
993 °C, and the melting point of calcium fluo-
ride, CaF 2 , is 1,423°C. Which of the following
best explains why the melting point of calcium
fluoride is higher?
(A) Sodium is a more reactive element than cal-
cium is.
(B) The sodium ion is smaller than the calcium
ion.
(C) The sodium ion has a lower charge than the
calcium ion.
(D) There are fewer fluoride ions in the formula
of sodium fluoride.
15. Pure phosphoric acid, H 3 PO 4 , freezes at about
42 °C. Which of the following best describes the
interactions in solid phosphoric acid?
(A) The solid consists of a collection of molecules
held together by London dispersion forces.
(B) The solid consists of a collection of atoms
held together by delocalized electrons.
(C) The solid consists of positive and negative
ions held together by ionic bonding.
(D) The solid consists of molecules held together
by intermolecular dipole–dipole interactions