Practice Problems 17
Chapter 12
CHE 151
Graham/08
1.)
Identify the strongest Interparticle force in the Liquid state of each:
a.) O2
__london_____________
b.) HF _____hydrogen bonding_____
c.) CH3OH _ hydrogen bonding
d.) N2 ____ london _______________
e.) NO _dipole-dipole___________
f.) CH3 COCH3 _ dipole-dipole ____
g.) Cl2 ____ london ____________
h.) HCCl3 _ dipole-dipole __________
i.) H2N – NH2 _ hydrogen bonding
j.) C3H8 _______ london ___________
k.) C3H7OH ___ hydrogen bonding _ l.) CCl4 ______ london ____________
m.) Ar ______ london ____________ n.) NH3 ___ hydrogen bonding _____
o.) H2SO4 __ hydrogen bonding ___
2.)
p.) H2C=CH2 _____ london ________
Predict (circle) which member of each pair has the higher boiling point
a.) F2
or
c.) N2
or
e.) NaI
Cl2
NO
or HI
g.) F
F
C=C
H
b.) HF
H
or
or
HBr
d.) C2H6
or O2
f.)
or H2S
H2 O
F
C=C
H
F
h.) HOCH2CH2OH
or
i.) CH3CH2CH2CH3
or CH3CHCH3
H
CH3CH2CH2OH
CH3
3.)
Which of the following is not a factor in determining the magnitude of the vapor
pressure of a liquid?
a.
b.
c.
d.
the temperature of the liquid
the strength of the attractive forces between molecules of the liquid
the size of the container for the liquid
the type of forces between molecules within the liquid
_____c_______
4.)
A nonvolatile liquid would
a.
b.
c.
d.
e.
5.)
have weak attractive forces between molecules
evaporate rapidly at room temperature
have a high vapor pressure at room temperature
be a very "explosive" substance
have strong attractive forces between molecules
_____e_________
Which statement about the boiling point of water is incorrect?
The boiling point is greater than 100oC in a pressure cooker.
The boiling point is less than 100oC for locations at low elevations.
At sea level and at a pressure of 760 mm Hg, the boiling point is 100oC.
In a pressure cooker, shorter cooking times are required due to the change in
boiling point.
d. The boiling point is a consequence of a molecule's intermolecular forces.
a.
b.
c.
d.
____b__________
6.)
Which of the following statements is correct?
a.
b.
c.
d.
dipole-dipole interactions occur only between nonpolar molecules
a hydrogen bond is an extremely weak dipole-dipole interaction
London forces are "instantaneous" dipole-dipole interactions
Hydrogen bonding occurs between any two hydrogen-containing molecules
____c__________
7.)
Which of the following substances would be expected to have the lowest boiling point?
a.
b.
c.
d.
e.
8.)
a nonpolar liquid
a polar liquid with hydrogen bonding
a polar liquid with weak dipole-dipole interactions
a nonvolatile liquid
a polar liquid with strong dipole-dipole interactions
____a_________
Which of the following compounds is incorrectly matched with the predominant
intermolecular force associated with that compound in the liquid state.
compound
a. CCl4
b. H2O
c. BF3
d. NH3
e. Br2
intermolecular force
dipole-dipole interactions
hydrogen bonding
London forces
hydrogen bonding
London forces
____a________
9.)
The normal boiling point of a substance is determined by its molecular mass and its
intermolecular forces. Considering these two factors, predict the order of increasing
boiling points for the following substances: H2, NaCl, H2O, and CO2.
a.
b.
c.
d.
e.
10.)
11.)
CO2 < H2 < NaCl < H2O
H2 < CO2 < H2O < NaCl
H2O < NaCl < CO2 < H2
H2 < NaCl < H2O < CO2
NaCl < H2O < CO2 < H2
____b________
The vapor pressure of PBr3 reaches 400 mm Hg at 150oC. The vapor pressure of PCl3
reaches 400 mm Hg at 57oC.
a. At 100oC which substance should evaporate at the faster rate?
____PCl3_____
b. Which substance should have the lower normal boiling point?
____ PCl3____
c. Which substance should have the weaker intermolecular forces?
____ PCl3___
d. At 50oC which substance should have the higher vapor pressure?
____ PCl3____
Consider the phase diagram shown below.
a. What phase(s) is/are present at point A?
___liquid_____________________
b. What phase(s) is/are present at point B? _solid, liquid, gas_______________
c. Name point C and explain its significance. _critical point- above the critical
temp., substance cannot be liquefied, regardless of pressure._________________
d. Starting at D, if the pressure is lowered while the temperature remains constant,
describe what will happen. D = solid phase. As P is lowered, solidgas dividing
line is reached. Solid will sublime. ___________
12.)
A.
B.
C.
D.
E.
13.)
Which of the following atoms should have the greatest polarizability?
F
Br
Po
Pb
He
____D________
In which of the following compounds will the molecules not form hydrogen
bonds with each other?
_____c______
14.)
A.
B.
C.
D.
E.
15.)
A.
B.
C.
D.
E.
Which of the following pairs is arranged with the particle of higher
polarizability listed first?
Se2-, S2I, IMg2+, Mg
Br, I
None of these choices is correct
____A_______
Select the pair of substances in which the one with the higher vapor pressure
at a given temperature is listed first.
C7H16, C5H12
CCl4, CBr4
H2O, H2S
CH3CH2OH, CH3-O-CH3
Xe, Kr
_____B_______
16.)
Which of the following should have the highest surface tension at a given
temperature?
A.
B.
C.
D.
E.
17.)
CH4
CF4
CCl4
CBr4
CI4
_____E________
Which of the following should have the highest surface tension at a given
temperature?
_____d_____
18.)
When the adhesive forces between a liquid and the walls of a capillary tube
are greater than the cohesive forces within the liquid
A.
the liquid level in a capillary tube will rise above the surrounding liquid and
the surface in the capillary tube will have a convex meniscus.
the liquid level in a capillary tube will rise above the surrounding liquid and
the surface in the capillary tube will have a concave meniscus.
the liquid level in a capillary tube will drop below the surrounding liquid and
the surface in the capillary tube will have a convex meniscus.
the liquid level in a capillary tube will drop below the surrounding liquid and
the surface in the capillary tube will have a concave meniscus.
None of these will occur.
B.
C.
D.
E.
_____B_________
19.)
Which of the following factors contributes to a low viscosity for a liquid?
A.
B.
C.
D.
E.
low temperature
spherical molecular shape
hydrogen bonding
high molecular weight
high boiling point
____B_______
20.)
Which of the following pairs of substances is arranged so that the one with
higher viscosity is listed first?
____b______
21.) Which of the following liquid substances would you expect to have the lowest
surface tension?
A.
B.
C.
D.
E.
Pb
CH3OCH3
HOCH2CH2OH
H2O
CH3CH2OH
____B_______
22.) Which one of the following substances does not exist in the indicated solid
type?
A.
B.
C.
D.
E.
graphite - network
Na - metallic
SiO2 - molecular
NaCl - ionic
diamond – network
_____C______
23.) When liquid bromine is cooled to form a solid, which of the following types of solid
would it form?
A.
B.
C.
D.
E.
atomic
metallic
molecular
ionic
covalent network
_____C______
24.)
A.
B.
C.
D.
E.
25.)
For the solid forms of the following elements, which one is most likely to be of
the molecular type?
Xe
C
Pb
S
Cr
_____D_____
Of the five major types of crystalline solid, which would you expect each of
The following to form? (e.g., H2O: molecular)
A. Sn ____metallic__________
B. Si
____network covalent__
C. KCl ____ionic____________
D. Xe _____atomic__________
E. F2 ____molecular_________