Homework 3-problems - ihm(jhi89 Homework 3 holcombe(51395...

ihm (jhi89) – Homework 3 – holcombe – (51395) 1
This print-out should have 25 questions.
Multiple-choice questions may continue on
the next column or page – find all choices
before answering.
001 4.0points
Consider dissolving gases in water. Which of
the following gases will become less soluble if
the temperature of the water is raised?
1. all of these
2. He
002 4.0points
What will be the freezing point of a solution
of 4 moles of sodium dichromate (Na
2
Cr
2
O
7
)
dissolved in 8 kg of water? Use the following
values:
K
b
= 0 . 512 K · m
− 1
K
f
= 1 . 86 K · m
− 1
1. 271 . 6 K
2. 272 . 2 K
3. 264 . 6 K
4. 269 . 4 K
5. 270 . 2 K
003 4.0points
Several interesting observations from the
world around you are listed below. Which
of these is NOT explained by a colligative
property?
3. Antifreeze is added to a car radiator to
keep the car from overheating.
4. Water boils at a higher temperature when
salt is added.
5. At high altitude it takes longer to cook
spaghetti.
The colligative effects of 1 molal sugar solu-
tion would be ?
3. the same as
005 4.0points
If ethylene glycol has a pure vapor pressure
of 28 torr and acetaldehyde has a pure vapor
pressure of 756 torr A mixture of 6 moles of
ethylene glycol and 1 moles of acetaldehyde
would have what total vapor pressure?
1. 132 torr
2. 108 torr
3. 672 torr
4. 24 torr
5. 112 torr
006 4.0points
The vapor pressure of pure acetone
(CH
3
COCH
3
) at 30
o
C is 240 torr. The va-
por pressure of pure water (H
2
O) at 30
o
C is
40 torr. If the total vapor pressure of a mix-
ture of water and acetone at 30
o
C is 190 torr,
what is the mol fraction of acetone?

ihm (jhi89) – Homework 3 – holcombe – (51395) 2