Q: Which equation correctly represents the enthalpy change of solution formation?

$\Delta H_{\text{solution}} = \Delta H_{\text{solute}} + \Delta H_{\text{solvent}} + \Delta H_{\text{mix}}$

Q: Which of the following is the correct formula for calculating the percent by mass of a solute in a solution?

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

Question 1

In cold winters, the wood frog partially freezes and survives by accumulating large amounts of glucose in its body fluids. What is the primary chemical effect of this adaptation?

Accepted Answer

It lowers the freezing point of the frog's body fluids, acting like an antifreeze.

Question 2

Which of the following best describes entropy in the context of solution formation?

Accepted Answer

Entropy is a measure of energy randomization or dispersal in a system.

Question 3

When a solute dissolves in a solvent, which of the following statements about the energetics of solution formation is correct?

Accepted Answer

Separating solute and solvent particles is generally endothermic because energy is required to break the forces.

Question 4

Which equation correctly represents the enthalpy change of solution formation?

Accepted Answer

$\Delta H_{	ext{solution}} = \Delta H_{	ext{solute}} + \Delta H_{	ext{solvent}} + \Delta H_{	ext{mix}}$

Question 5

If $\Delta H_{	ext{solution}} > 0$, what drives the formation of a solution?

Accepted Answer

The increasing entropy upon mixing ($\Delta S$) can drive the formation of a solution even if the process is endothermic.

Question 6

Which of the following statements about the solubility of gases in water is correct?

Accepted Answer

The solubility of gases in water decreases with increasing temperature.

Question 7

Which law describes the relationship between the partial pressure of a gas above a liquid and its solubility in the liquid?

Accepted Answer

Henry's Law

Question 8

A solution is prepared by dissolving 2.0 moles of NaCl in enough water to make 1.0 L of solution. What is the molarity of the solution?

Accepted Answer

$2.0\ 	ext{M}$

Question 9

Which of the following best explains why 'like dissolves like' in terms of solubility?

Accepted Answer

Polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes because similar intermolecular forces are present.

Question 10

Which of the following is a correct statement about saturated, unsaturated, and supersaturated solutions?

Accepted Answer

A supersaturated solution contains more solute than a saturated solution at the same temperature.

Question 11

Which of the following best describes the effect of adding a nonvolatile solute to a solvent?

Accepted Answer

It lowers the freezing point and vapor pressure of the solvent.

Question 12

A 0.1 m NaCl solution is prepared. Assuming complete dissociation, what is the total concentration of dissolved particles in the solution?

Accepted Answer

$0.2\ 	ext{mol/L}$

Question 13

Which of the following is the correct formula for calculating the percent by mass of a solute in a solution?

Accepted Answer

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

Question 14

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

Accepted Answer

Solubility increases as temperature increases.

Question 15

A solution is prepared by dissolving 10.0 g of KCl in 100.0 g of water. What is the percent by mass of KCl in the solution?

Accepted Answer

$9.09\%$

Question 16

Which of the following is a real-life application of colligative properties?

Accepted Answer

Using salt to melt ice on roads in winter by lowering the freezing point of water.

Question 17

Which of the following statements about dynamic equilibrium in a saturated solution is correct?

Accepted Answer

The rate of dissolution of solute equals the rate of precipitation.

Question 18

Which of the following best explains why the entropy of a system increases when a solute dissolves in a solvent?

Accepted Answer

The solute and solvent particles are more randomly distributed.

Question 19

Which of the following is NOT a type of solution?

Accepted Answer

Solid in solid cannot form a solution

Question 20

A student adds more solute to a solution and observes that it does not dissolve. What can be concluded about the solution?

Accepted Answer

The solution is saturated.

Solutions and Solution Formation: Energetics and Solubility

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