Question 1

Which of the following best explains why wood frogs can survive freezing temperatures, unlike most other cold-blooded animals?

Accepted Answer

They flood their blood with glucose, creating a concentrated solution that lowers the freezing point of their body fluids.

Question 2

Which of the following statements about solutions is correct?

Accepted Answer

A solution is a homogeneous mixture that can be composed of different phases, such as a gas in a liquid.

Question 3

Which of the following best describes the driving force for the spontaneous mixing of two ideal gases?

Accepted Answer

The release of entropy, which disperses energy throughout the system.

Question 4

Which of the following pairs is most likely to form a solution based on the principle 'like dissolves like'?

Accepted Answer

Methanol (polar) and water (polar)

Question 5

Which process is always exothermic during the formation of a solution?

Accepted Answer

Forming new solute–solvent attractions

Question 6

A solution is prepared by dissolving 17.2 g of ethylene glycol (C$$_2H$_6O$_2$$, molar mass = 62.07 g/mol) in 0.500 kg of water. What is the molality ($$m) of $$the solution?

Accepted Answer

$$m = \frac{17.2/62.07}{0.500}$$

Question 7

Which of the following statements about colligative properties is true?

Accepted Answer

They depend only on the number of solute particles present.

Question 8

A solution is made by dissolving a nonvolatile solute in water. Which of the following will occur?

Accepted Answer

The vapor pressure of the solution will be lower than that of pure water.

Question 9

Which equation correctly expresses Raoult’s Law for the vapor pressure of a solvent in a solution?

Accepted Answer

$$P_{solution} = X_{solvent} P^*_{solvent}$$

Question 10

A solution is prepared by mixing 50 g of water (molar mass = 18.02 g/mol, $$P^*_{H_2O} = 23.8$$ mmHg) and 50 g of ethanol (molar mass = 46.07 g/mol, $$P^*_{C_2H_5OH} = 58.7$$ mmHg). What is the mole fraction of water in the solution?

Accepted Answer

$$X_{H_2O} = \frac{50/18.02}{(50/18.02)+(50/46.07)}$$

Question 11

Which of the following best describes a supersaturated solution?

Accepted Answer

A solution that contains more solute than the saturation concentration and is unstable.

Question 12

Which of the following changes will increase the solubility of a gas in water?

Accepted Answer

Decreasing the temperature and increasing the pressure.

Question 13

Which equation correctly expresses the relationship described by Henry’s Law?

Accepted Answer

$$C = k_H P_{gas}$$

Question 14

A solution is prepared by dissolving 50.0 g of hemoglobin in enough water to make 1.00 L of solution. The osmotic pressure is measured to be 14.3 mmHg at 25°C. Which equation would you use to calculate the molar mass of hemoglobin?

Accepted Answer

$$\pi = MRT$$

Question 15

Which of the following best describes the effect of adding a nonvolatile solute to a solvent on the freezing and boiling points of the solution?

Accepted Answer

The freezing point decreases and the boiling point increases.

Question 16

Which of the following is the correct formula for calculating the freezing point depression of a solution?

Accepted Answer

$$\Delta T_f = i K_f m$$

Question 17

A red blood cell is placed in a hypotonic solution. What will happen to the cell?

Accepted Answer

It will swell as water enters the cell.

Question 18

Which of the following best explains why the measured van’t Hoff factor ($$i) $$for an ionic compound is often less than the theoretical value?

Accepted Answer

Some ions pair together in solution, reducing the number of effective particles.

Question 19

Which of the following is a real-life application of freezing point depression?

Accepted Answer

Using salt to melt ice on roads during winter.

Chapter 13: Solutions – Structure, Properties, and Colligative Effects

Guida di studio - Domande di pratica

Study guide - Flashcard