Boiling Point Elevation Practice
1. If I add 45 grams of sodium chloride to 500 grams of water, what will the boiling point be of
the resulting solution?
2. Which solution will have a higher boiling point: A solution containing 105 grams of sucrose
(C12H22O11) in 500 grams of water or a solution containing 35 grams of sodium chloride in 500
grams of water?
3. If the boiling point of 69.9 g CCl4 is raised by 10.2°C, how many grams of pyridine (C5H5N)
must be dissolved in it? (Tb = 76.5°C, Kb = 3.63°C/m for CCl4)
4. What is the boiling point elevation when 43.5 g of the dye magenta I (C20H20ClN3) is
dissolved in 1650 g of ethanol? (Tb = 78.4°C, Kb = 1.22°C/m for ethanol)
5. What is the molar mass of glucose if a solution containing 18.00 g of glucose in 150 g of water
boils at 100.34°C?
Freezing Point Depression Practice
1. When 15.0g of ethyl alcohol, C2H5OH, is dissolved in 750 grams of formic acid, the freezing
point of the solution is 7.20°C. The freezing point of pure formic acid is 8.40°C. Solve for Kf for
formic acid.
2. A 1.20 gram sample of an unknown covalent compound is dissolved in 50.0 g of benzene.
The solution freezes at 4.92°C. Calculate the molecular weight of the compound. The freezing
point of pure benzene is 5.48°C and Kf is 5.12°C/m.
3. Vitamin K is involved in the blood clotting mechanism. When 0.500 g is dissolved in 10.0 g of
camphor, the freezing point is lowered by 4.43 °C. Calculate the molecular weight of vitamin K,
knowing that Kf is 40°C/m for camphor.
4. Which will lower the freezing point of 500 g of water more; 59 g of sodium chloride, or 90 g
of magnesium chloride?