Colligative Properties Practice
1. You have a 100.0gram sample of C12H22O11 dissolved in 500ml of water at 20C. The vapor
pressure of water is 17.54mmHg. Kb = 0.51 Kf = 1.86 Calculate each of the following:
Molarity
Molality
Mole Fraction Mass percent
Vapor Pressure
Boiling Point
Freezing Point.
2. You are given four 100ml sample of the following solutions: 0.10M NaF, 0.10M MgCl2, 0.10M
C2H5OH and 0.10M CH3COOH
a. Which solution has the lowest freezing point? Why?
b. Which solution will have the highest vapor pressure in a closed container? Why?
c.
d. Which solution has the highest boiling point? Why?
3. Explain each of the following observations using the appropriate chemical principles.
a. When NaCl and sugar are each dissolved in water, each solution has a higher boiling
point than that of pure water.
b. The boiling point of 0.20m NaCl is higher than that if C12H22O11
c. A solution of iodine dissolved in water has a vapor pressure that exhibits a positive
deviation from Raoult’s Law
d. A solution of CuSO4 dissolved in water has a vapor pressure that exhibits a megative
deviation from Raoult’s Law.
4. Use the following data to create a linear plot which will allow you to solve for the Hvap
Temp (C)
P(torr)
7.0
32.42
27.0
92.47
47.0
225.1
57.0
334.4
67.0
482.9
5. Use the following phase diagram to determine if each statement is true or false. If the statement
is false, correct it to become a true statement.
a.
b.
c.
d.
e.
f.
The critical temperature of the substance is -57C
The substance cannot boil
At 6.0 atm, the liquid is more dense than the solid
At 1.0 atm, the substance cannot exist as a liquid
Only the solid phase exists at point A
The substance changes from a gas to a liquid from point B if the pressure is decreased