CH302 Worksheet 2—Colligative Properties
All of this is intended to be done without the aid of a calculator. All of the calculations are designed such
that approximating should be straightforward and produce a correct result.
1. Based on the physical constants involved, which colligative property has the greatest magnitude for a
solution of a given concentration? Which can't be compared in this way? Why?
2. Which colligative properties have a linear concentration dependence? Write their equations.
3. Rank the following aqueous solutions in terms of increasing boiling point: 3
m
sugar, 2
m
NaCl, 0.5
m
Mg(OH)
2
, 5
m
AlN, 1
m
urea.
4. Assuming a cell wall can withstand an osmotic pressure of 1 atmosphere and the concentration of
Na
+
in a cell is 50 mM, approximate the [Na
+
] outside the cell that would cause lysis.
5. If you dissolved 28 grams of NaCl in 90 grams of pure H
2
0 hot enough to have a vapor pressure of
30 torr, what will the new vapor pressure be?
6. Assuming standard conditions and a K
f
= 0.2 K·
m
1
and a K
b
= 0.5 K·
m
1
for water, what would be
the freezing point of a solution that boiled at 375.5 K? Express your answer in both K and °C.
7. Based on the question above and assuming 1 kg of water, how many moles of NaCl would be needed
to produce this effect? What about sugar?
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 Spring '10
 Laude
 pH, Vapor pressure

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