AP Chemistry - Colligative Properties

1

At room temperature, hexane has a vapor pressure of and ethanol has a vapor pressure of . A solution of these two solvents at room temperature has a vapor pressure of . What percentage of the solution is ethanol?

2

What is the melting point of a aqueous solution that contains of $MgCl_{2}$ ?

$k_{f\ H_2O}=1.86$

$\rho_{H_2O}=1\frac{g}{mL}$

3

A solution of of water and of glucose has a freezing point depression of $1.24^{\circ}C$ . Which of the following changes would NOT triple the original change in the melting point?

4

What is the freezing point of a 2M solution of in water?

$\small k_f_{water}=1.853\frac{C^okg}{mol}$

5

It is snowing outside and you decide to throw salt onto the driveway. What is the purpose of throwing salt onto the driveway?

6

You are attempting to distill the water from a sample of seawater. What can you do to facilitate the process?

7

The vapor pressure of ethanol at room temperature is 45mmHg. A nonvolatile solute is added to a vial of ethanol, resulting in a solution with a vapor pressure of 34mmHg. What is the molar fraction of the nonvolatile solute in the solution?

8

50g of an unknown compound are added to three kilograms of water. The compound is nonvolatile, and has a van't Hoff factor of 2. It is determined that the solution has a freezing point of $\small -2.50^oC$ .

What is the molar mass of the unknown compound?

$\small k_{f\ water}=1.86\frac{^oCkg}{mol}$

9

Which of the following solutions has the highest boiling point?

Assume that all solutes in solution are nonvolatile.

10

The vapor pressure of water is at . Two moles of a nonvolatile solute are added to eight moles of water. What is the vapor pressure of this solution?

Colligative Properties

Practice Questions