Homework Answers

1. What is the boiling point and freezing point of a solution containing 6 g of

glycerol (C3H8O3) in 25 g of water?

2. What is the molecular mass of a solute in a solution containing 3.8 g of

nonelectrolyte in 420 g of water which freezes at -23 oC?

Identify what colligative property is applied or observed in the following. Explain

your answer.

1. Salt is mixed with ice in ice cream making.

2. Salt and sugar are used in food preservation.

3. Coolant is added to car radiators.

4. Pressure cooker.

5. Pruned or wrinkled fingers.

Solve for what is being asked.

What is the molar mass of the solute in a solution made by dissolving 34.41

g of an unknown nonelectrolyte compound in 280.0 g benzene. The boiling point of

the solution is 93.2 °C. Benzene has a boiling point of 80.1 °C and molal boiling-

point elevation constant of 2.53 °C/m.

Solve the given problem.

What is the molality of a solution prepared from 29.22 grams of NaCl in 2.00

kg of water?

Given: mass of solute = 29.22 g

Mass of solvent = 2 kg

Required: m = ?

Solution: m = mole of solute/kg solvent

n = 29.22 g x 1 mol/ 58.44 g

n = 0.5 mol

m = 0.5 mol/ 2 kg

Final Answer: m = 0.25 mol/kg

Given the following equation: 2 C4H10 + 13 O2 ---> 8 CO2 + 10 H2O, show what the following molar ratios should be.