Practice Problems 2

Practice Problems 17 Chapter 12 CHE 151
Graham/08
1.) Identify the strongest Interparticle force in the Liquid state of each:
a.) O 2 __london_____________ b.) HF _____hydrogen bonding_____
c.) CH 3 OH _ hydrogen bonding
e.) NO _dipole-dipole___________
g.) Cl 2 ____ london ____________
i.) H 2 N – NH 2 _ hydrogen bonding
d.) N 2 ____ london _______________
f.) CH 3 COCH 3 _ dipole-dipole ____
h.) HCCl 3 _ dipole-dipole __________
j.) C 3 H 8 _______ london ___________
k.) C 3 H 7 OH ___ hydrogen bonding _ l.) CCl 4 ______ london ____________
m.) Ar ______ london ____________ n.) NH 3 ___ hydrogen bonding _____
o.) H 2 SO 4 __ hydrogen bonding ___ p.) H 2 C=CH 2 _____ london ________
2.) Predict (circle) which member of each pair has the higher boiling point
a.) F 2 or Cl 2 b.) HF or HBr
c.) N 2 or NO d.) C 2 H 6 or O 2
e.) NaI or HI f.) H 2 O or H 2 S
g.) F F H F
C=C or C=C
H H F H
h.) HOCH 2 CH 2 OH or CH 3 CH 2 CH 2 OH
i.) CH 3 CH 2 CH 2 CH 3 or CH 3 CHCH 3
CH 3
3.) Which of the following is not a factor in determining the magnitude of the vapor
pressure of a liquid
a. the temperature of the liquid
b. the strength of the attractive forces between molecules of the liquid
c. the size of the container for the liquid
d. the type of forces between molecules within the liquid
_____c_______

4.) A nonvolatile liquid would
a. have weak attractive forces between molecules
b. evaporate rapidly at room temperature
c. have a high vapor pressure at room temperature
d. be a very "explosive" substance
e. have strong attractive forces between molecules _____e_________
5.) Which statement about the boiling point of water is incorrect
a. The boiling point is greater than 100 o C in a pressure cooker.
b. The boiling point is less than 100 o C for locations at low elevations.
c. At sea level and at a pressure of 760 mm Hg, the boiling point is 100 o C.
d. 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.
____b__________
6.) Which of the following statements is correct
a. dipole-dipole interactions occur only between nonpolar molecules
b. a hydrogen bond is an extremely weak dipole-dipole interaction
c. London forces are "instantaneous" dipole-dipole interactions
d. 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. a nonpolar liquid
b. a polar liquid with hydrogen bonding
c. a polar liquid with weak dipole-dipole interactions
d. a nonvolatile liquid
e. a polar liquid with strong dipole-dipole interactions ____a_________
8.) Which of the following compounds is incorrectly matched with the predominant
intermolecular force associated with that compound in the liquid state.
compound intermolecular force
a. CCl4 dipole-dipole interactions
b. H2O hydrogen bonding
c. BF3 London forces
d. NH3 hydrogen bonding
e. Br2 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. CO2 < H2 < NaCl < H2O
b. H2 < CO2 < H2O < NaCl
c. H2O < NaCl < CO2 < H2
d. H2 < NaCl < H2O < CO2
e. NaCl < H2O < CO2 < H2 ____b________
10.) The vapor pressure of PBr 3 reaches 400 mm Hg at 150 o C. The vapor pressure of PCl 3
reaches 400 mm Hg at 57 o C.
a. At 100 o C which substance should evaporate at the faster rate ____PCl 3 _____
b. Which substance should have the lower normal boiling point ____ PCl 3 ____
c. Which substance should have the weaker intermolecular forces ____ PCl 3 ___
d. At 50 o C which substance should have the higher vapor pressure ____ PCl 3 ____
11.) 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, solidgas dividing
line is reached. Solid will sublime. ___________

12.) Which of the following atoms should have the greatest polarizability
A. F
B. Br
C. Po
D. Pb
E. He ____D________
13.) In which of the following compounds will the molecules not form hydrogen
bonds with each other
14.) Which of the following pairs is arranged with the particle of higher
polarizability listed first
_____c______
A. Se 2- , S 2-
B. I, I -
C. Mg 2+ , Mg
D. Br, I
E. None of these choices is correct ____A_______
15.) Select the pair of substances in which the one with the higher vapor pressure
at a given temperature is listed first.
A. C 7 H 16 , C 5 H 12
B. CCl 4 , CBr 4
C. H 2 O, H 2 S
D. CH 3 CH 2 OH, CH 3 -O-CH 3
E. Xe, Kr _____B_______

16.) Which of the following should have the highest surface tension at a given
temperature
A. CH 4
B. CF 4
C. CCl 4
D. CBr 4
E. CI 4 _____E________
17.) Which of the following should have the highest surface tension at a given
temperature
18.) When the adhesive forces between a liquid and the walls of a capillary tube
are greater than the cohesive forces within the liquid
_____d_____
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.
B. 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.
C. 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.
D. 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.
E. None of these will occur.
_____B_________
19.) Which of the following factors contributes to a low viscosity for a liquid
A. low temperature
B. spherical molecular shape
C. hydrogen bonding
D. high molecular weight
E. high boiling point ____B_______

20.) Which of the following pairs of substances is arranged so that the one with
higher viscosity is listed first
21.) Which of the following liquid substances would you expect to have the lowest
surface tension
____b______
A. Pb
B. CH 3 OCH 3
C. HOCH 2 CH 2 OH
D. H 2 O
E. CH 3 CH 2 OH ____B_______
22.) Which one of the following substances does not exist in the indicated solid
type
A. graphite - network
B. Na - metallic
C. SiO 2 - molecular
D. NaCl - ionic
E. diamond – network _____C______
23.) When liquid bromine is cooled to form a solid, which of the following types of solid
would it form
A. atomic
B. metallic
C. molecular
D. ionic
E. covalent network _____C______

24.) For the solid forms of the following elements, which one is most likely to be of
the molecular type
A. Xe
B. C
C. Pb
D. S
E. Cr _____D_____
25.) Of the five major types of crystalline solid, which would you expect each of
The following to form (e.g., H 2 O: molecular)
A. Sn ____metallic__________
B. Si ____network covalent__
C. KCl ____ionic____________
D. Xe _____atomic__________
E. F 2 ____molecular_________