Q: Which equation correctly expresses molarity (M)?

$M = \frac{\text{amount solute (in mol)}}{\text{volume solution (in L)}}$

Q: Which of the following is the correct expression for percent by mass?

$\text{Percent by mass} = \frac{\text{mass solute}}{\text{mass solution}} \times 100\%$

Question 1

Which of the following best explains why sodium chloride (NaCl) dissolves spontaneously in water, as shown in the first image?

Accepted Answer

The process increases the entropy of the system, dispersing energy over a larger volume.

Question 2

Which of the following is an example of a solid solution, based on the types of solutions in Table 14.1?

Accepted Answer

Brass (copper and zinc)

Question 3

A student adds 10 g of NaCl to 100 g of water and observes that all the salt dissolves. Which term best describes this solution?

Accepted Answer

Unsaturated

Question 4

Which intermolecular force is primarily responsible for the solubility of ethanol (CH$_3$CH$_2$OH) in water?

Accepted Answer

Hydrogen bonding

Question 5

According to the 'like dissolves like' rule, which solvent would best dissolve vitamin A (structure shown above)?

Accepted Answer

Hexane (C$_6$H$_{14}$)

Question 6

Which of the following statements about the enthalpy of solution ($\Delta H_{soln}$) is correct?

Accepted Answer

$\Delta H_{soln}$ is the sum of $\Delta H_{solute}$, $\Delta H_{solvent}$, and $\Delta H_{mix}$.

Question 7

A solution is prepared by dissolving 20.2 mL of methanol (density = 0.782 g/mL) in 100.0 mL of water (density = 1.00 g/mL) at 25°C. What is the mass percent of methanol in the solution? (Final volume = 118 mL)

Accepted Answer

14.6%

Question 8

Which of the following best describes the effect of increasing temperature on the solubility of most solid solutes in water?

Accepted Answer

Solubility increases with increasing temperature.

Question 9

Which equation correctly expresses molarity (M)?

Accepted Answer

$M = \frac{	ext{amount solute (in mol)}}{	ext{volume solution (in L)}}$

Question 10

A solution is made by dissolving 55.3 g of KNO$_3$ in enough water to make 2.00 L of solution. What is the molarity of the solution? (Molar mass KNO$_3$ = 101.1 g/mol)

Accepted Answer

0.274 M

Question 11

Which of the following best explains why gases are less soluble in water at higher temperatures?

Accepted Answer

Gas molecules have higher kinetic energy and escape more easily from the solution.

Question 12

Which of the following is the correct expression for percent by mass?

Accepted Answer

$	ext{Percent by mass} = \frac{	ext{mass solute}}{	ext{mass solution}} 	imes 100\%$

Question 13

Which of the following statements about solution equilibrium is correct?

Accepted Answer

At equilibrium, the rate of dissolution equals the rate of recrystallization.

Question 14

Which of the following best describes the role of entropy in the formation of solutions?

Accepted Answer

Entropy is a measure of energy dispersal and generally increases when a solution forms.

Question 15

Which of the following is a correct application of Henry's Law for the solubility of a gas in a liquid?

Accepted Answer

The solubility of a gas is directly proportional to its partial pressure above the solution.

Question 16

Which of the following best explains why vitamin C is water-soluble while vitamin A is fat-soluble?

Accepted Answer

Vitamin C contains many polar -OH groups, while vitamin A is mostly nonpolar.

Question 17

Which of the following is the correct formula for molality (m)?

Accepted Answer

$m = \frac{	ext{amount solute (in mol)}}{	ext{mass solvent (in kg)}}$

Question 18

A solution contains 16.65% naphthalene (C$_{10}$H$_8$) by mass in hexane (C$_6$H$_{14}$). If the vapor pressure of pure hexane at 25°C is 151 torr, what is the vapor pressure of hexane above the solution? (Assume naphthalene is nonvolatile.)

Accepted Answer

126 torr

Question 19

Which of the following best describes the interactions that must be considered when a solution forms?

Accepted Answer

Solute-solute, solvent-solvent, and solute-solvent interactions

Chapter 14: Solutions – Structure, Properties, and Calculations

Study Guide - Practice Questions

Study Guide - Flashcards