Version 029 – hw02 – Holcombe – (53570)
1
This
print-out
should
have
25
questions.
Multiple-choice questions may continue on
the next column or page – find all choices
before answering.
00110.0 pointsAt 75◦, the vapor pressure of water, methanol,diethylether and benzene are 289, 1126, 2680,and 644 torr, respectively. Which of these isNOT above its boiling point at normal atmo-spheric pressure?
1.methanol, diethylether, and benzene
2.
diethylether
3.
methanol and diethylether
002
10.0 points
What is the vapor pressure of carbon disulfideat its normal boiling point?
003
10.0 points
The solubility of a gas such as O2in water(decreases, increases, stays the same) withincreasing temperature.
004
10.0 points
According to Henry’s Law, the concentrationof gas dissolved in water has what relationshipto the pressure of the gas?
00510.0 pointsWhich of the following is a FALSE state-ment?
Version 029 – hw02 – Holcombe – (53570)
2
increasing temperature.
Explanation:
Gases become more soluble as pressures
increases and temperatures decrease.
006
10.0 points
The solubility of oxygen at a certain tempera-
ture is 8 ppm. If the partial pressure of oxygen
is doubled at this temperature, the solubility
is 16 ppm.
1.
True
correct
2.
False
Explanation:
007
10.0 points
Hint: The units for Henry’s constant should
indicate what form of Henry’s Law to use.
Calculate the number of moles of oxygen
that will dissolve in 45 L of water at 20
◦
C
if the partial pressure of oxygen is 0.21 atm.
Henry’s constant for oxygen is 0.0013
mol
L
·
atm
.
1.
0.0062 mol
2.
0.012 mol
correct
3.
0.28 mol
4.
0.00027 mol
5.
0.0013 mol
Explanation:
008
10.0 points
What is the vapor pressure of the solvent in
an aqueous solution of glucose at 80
◦
C if the
mole fraction of glucose is 0
.
09?
The vapor
pressure of water at 80
◦
C is 355
.
26 Torr.
