Question 1

Which of the following statements best describes colligative properties?

Accepted Answer

They depend on the concentration of solute particles, independent of the solute's identity.

Question 2

A solution is prepared by dissolving 1.0 mol KBr in water. What is the particle concentration of the solution?

Accepted Answer

2.0 m

Question 3

Which equation correctly expresses Raoult’s law for vapor pressure lowering?

Accepted Answer

$$P_\mathrm{soln} = X_\mathrm{solv} P_\mathrm{solv}$$

Question 4

A solution contains 0.39 mol of cholesterol in 5.4 mol of toluene at 32°C. The vapor pressure of pure toluene at 32°C is 41 torr. What is the vapor pressure lowering ($$\Delta P) of $$the solution?

Accepted Answer

3.0 torr

Question 5

Which of the following best explains why the boiling point of a solution is higher than that of the pure solvent?

Accepted Answer

The presence of solute particles lowers the vapor pressure, requiring a higher temperature to reach boiling.

Question 6

Calculate the boiling point of a solution containing 3.4 g of vanillin (152.14 g/mol) dissolved in 50.0 g of ethanol. The boiling point elevation constant ($$K_b) $$for ethanol is 1.22 $$^\circC/m $$and the boiling point of pure ethanol is 78.5 $$^\circC.$$

Accepted Answer

0.55 $$^\circC$$

Question 7

Which equation is used to calculate the freezing point depression of a solution?

Accepted Answer

$$\Delta T_f = K_f m$$

Question 8

A solution is made by dissolving 8.00 g of CaCl$$_2 (110.98 g/$$mol) in 100.0 g of water. The freezing point depression constant ($$K_f) $$for water is 1.86 $$^\circC/m. $$What is the freezing point of the solution?

Accepted Answer

-1.34 $$^\circC$$

Question 9

Which of the following is NOT a colligative property?

Accepted Answer

Density increase

Question 10

Osmotic pressure ($$\Pi) of a $$solution can be calculated using which equation?

Accepted Answer

$$\Pi = MRT$$

Question 11

Reverse osmosis is used in water purification. Which statement best describes the process?

Accepted Answer

Pressure is applied to force water from a concentrated solution through a semipermeable membrane to obtain pure solvent.

Question 12

Which of the following best explains why salt is used to melt ice on roads in winter?

Accepted Answer

Salt decreases the freezing point of water, causing ice to melt at lower temperatures.

Question 13

A mixture of benzene and toluene is separated by fractional distillation. What property of the mixture allows this separation?

Accepted Answer

The vapor composition differs from the liquid composition due to differences in vapor pressures.

Question 14

Which of the following causes deviations from ideal colligative property behavior in real solutions?

Accepted Answer

Solute particles interact with each other.

Question 15

Which of the following best describes the driving force behind all colligative properties?

Accepted Answer

Entropy

Question 16

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the diffusion of solvent through a semipermeable membrane from low to high solute concentration.

Question 17

Which formula is used to calculate the vapor pressure of a solution containing both a volatile solute and a volatile solvent?

Accepted Answer

$$P_\mathrm{soln} = X_\mathrm{solv} P_\mathrm{solv} + X_\mathrm{solute} P_\mathrm{solute}$$

Question 18

Which of the following is a real-world application of boiling point elevation?

Accepted Answer

Using antifreeze in car radiators to prevent overheating.

Question 19

A solution is made by dissolving 0.5 mol NaCl in 1.0 kg of water. Assuming complete dissociation, what is the molality of solute particles?

Accepted Answer

1.0 m

Question 20

Which of the following best explains why mixtures have greater entropy than pure substances?

Accepted Answer

Mixtures have more types of particles and more possible arrangements.

Colligative Properties and Solution Behavior: Study Notes

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