Q: A solution is prepared by dissolving 10 g of NaCl in 90 g of water. What is the mass percent of NaCl in the solution?

$$\frac{10}{100} \times 100 = 10\%$$

Q: A solution is made by dissolving 0.5 mol of glucose (a non-electrolyte) in 1.0 kg of water. If $$K_f$$ for water is $$1.86\ ^\circ\mathrm{C}/m$$, what is the freezing point depression?

$$\Delta T_f = 1.86 \times 0.5 = 0.93\ ^\circ\mathrm{C}$$

Q: Which equation correctly represents Raoult’s Law for the vapor pressure of a solution?

$$P_{\text{solution}} = \chi_{\text{solvent}} P^\circ_{\text{solvent}}$$

Question 1

Which of the following best explains why mixing two different gases is a spontaneous process?

Accepted Answer

The process increases the entropy of the system.

Question 2

Which intermolecular force is primarily responsible for the solubility of NaCl in water?

Accepted Answer

Ion-dipole interactions

Question 3

A solution is prepared by dissolving 10 g of NaCl in 90 g of water. What is the mass percent of NaCl in the solution?

Accepted Answer

$$\frac{10}{100} 	imes 100 = 10\%$$

Question 4

Which of the following statements about supersaturated solutions is correct?

Accepted Answer

They contain more solute than is normally possible at that temperature.

Question 5

Which of the following best describes why hexane and water are immiscible?

Accepted Answer

Hexane is nonpolar and water is polar, so their intermolecular forces are not compatible.

Question 6

According to Henry’s Law, what happens to the solubility of a gas in a liquid if the partial pressure of the gas above the solution is doubled?

Accepted Answer

The solubility of the gas doubles.

Question 7

Which of the following is a colligative property?

Accepted Answer

Boiling-point elevation

Question 8

A solution is made by dissolving 0.5 mol of glucose (a non-electrolyte) in 1.0 kg of water. If $$K_f$$ for water is $$1.86\ ^\circ\mathrm{C}/m$$, what is the freezing point depression?

Accepted Answer

$$\Delta T_f = 1.86 	imes 0.5 = 0.93\ ^\circ\mathrm{C}$$

Question 9

Which of the following best explains why cold rivers have higher oxygen content than warm rivers?

Accepted Answer

The solubility of gases in water decreases as temperature increases.

Question 10

Which equation correctly represents Raoult’s Law for the vapor pressure of a solution?

Accepted Answer

$$P_{	ext{solution}} = \chi_{	ext{solvent}} P^\circ_{	ext{solvent}}$$

Question 11

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

Accepted Answer

It will swell and may burst (hemolysis).

Question 12

Which of the following is true about molality ($$m) $$and molarity ($$M$$)?

Accepted Answer

Molality does not change with temperature, but molarity does.

Question 13

Which of the following best describes the Tyndall effect?

Accepted Answer

The scattering of light by colloidal particles.

Question 14

A solution contains 0.2 mol NaCl (dissociates into 2 ions) and 0.1 mol glucose (does not dissociate) in 1 kg of water. What is the van’t Hoff factor ($$i) $$for this solution?

Accepted Answer

$$i = (0.2 	imes 2 + 0.1 	imes 1) / (0.2 + 0.1) = 0.5 / 0.3 \approx 1.67$$

Question 15

Which of the following is a correct statement about colligative properties?

Accepted Answer

They depend only on the number of solute particles, not their identity.

Question 16

Which of the following best explains why fat-soluble vitamins can be stored in the body, but water-soluble vitamins cannot?

Accepted Answer

Fat-soluble vitamins are nonpolar and accumulate in fatty tissues, while water-soluble vitamins are polar and are excreted in urine.

Question 17

A solution is prepared by dissolving 5 g of a nonvolatile solute in 95 g of water. The vapor pressure of pure water at 25$$^\circC is 23.8 $$torr. If the mole fraction of water in the solution is 0.98, what is the vapor pressure of the solution?

Accepted Answer

$$P_{	ext{solution}} = 0.98 	imes 23.8 = 23.3$$ torr

Question 18

Which of the following best describes the role of an emulsifier in a colloidal system?

Accepted Answer

It allows nonpolar substances to disperse in polar solvents.

Question 19

Which of the following equations correctly expresses osmotic pressure ($$\Pi) $$for a dilute solution?

Accepted Answer

$$\Pi = iMRT$$

Chapter 13: Properties of Solutions – General Chemistry Study Notes

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