Question 1

Which of the following best explains why the dissolution of gases in water is often exothermic?

Accepted Answer

The attraction between gas and water molecules releases more energy than is required to open pockets in water.

Question 2

A scuba diver is concerned about the solubility of oxygen in water at different depths. Which combination of temperature and pressure will maximize the amount of dissolved oxygen?

Accepted Answer

Low temperature and high pressure

Question 3

Which equation correctly describes the relationship between Gibbs free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T) $$for the dissolution of a solid in a liquid?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 4

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 too different to mix.

Question 5

A student observes that the solubility of ammonia ($$\mathrm{NH_3$}) in $$water decreases as the temperature increases. Which of the following best explains this observation?

Accepted Answer

The dissolution of ammonia in water is exothermic, so higher temperatures shift the equilibrium toward undissolved gas.

Question 6

Which of the following statements about the dissolution of ionic solids in water is correct?

Accepted Answer

Ion-dipole attractions between water and ions must overcome ion-ion attractions in the solid for dissolution to occur.

Question 7

Which of the following best describes the effect of increasing pressure on the solubility of nitrogen ($$\mathrm{N_2$}) in $$water?

Accepted Answer

Solubility increases because more gas molecules enter the solution.

Question 8

Which of the following is an example of a liquid-liquid solution that is miscible?

Accepted Answer

Water and ethanol

Question 9

A chemist wants to dissolve a polar solid in a solvent. According to the 'like dissolves like' rule, which solvent should they choose?

Accepted Answer

A polar solvent such as water

Question 10

Which of the following best explains why the solubility of most solids in water increases with temperature?

Accepted Answer

The entropy change ($$\Delta S) is $$positive, so increasing temperature makes $$\Delta G$$ more negative.

Question 11

Which of the following is NOT a requirement for the formation of a liquid-solid solution?

Accepted Answer

The solute must be nonpolar and the solvent must be polar.

Question 12

Which of the following scenarios would most likely result in an endothermic dissolution process?

Accepted Answer

Dissolving a gas in an organic solvent where energy required to open pockets exceeds energy released by attractions

Question 13

Which of the following best describes the process of hydration?

Accepted Answer

The surrounding of solute particles by water molecules

Question 14

A student mixes sugar (a polar solid) with benzene (a nonpolar solvent) and observes that the sugar does not dissolve. Which principle explains this observation?

Accepted Answer

Like dissolves like: polar solids dissolve in polar solvents.

Question 15

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

Accepted Answer

Solubility decreases with increasing temperature.

Question 16

Which of the following is a real-world example of a gas-liquid solution?

Accepted Answer

Carbon dioxide dissolved in water (carbonated beverages)

Question 17

Which of the following best describes the equilibrium involved in the dissolution of a gas in a liquid?

Accepted Answer

The equilibrium constant decreases with temperature, favoring undissolved gas.

Question 18

Which of the following would most likely be soluble in a nonpolar solvent such as benzene?

Accepted Answer

Wax (a nonpolar solid)

Question 19

Which of the following is the main reason why oil and water form two separate layers when mixed?

Accepted Answer

Oil and water have very different intermolecular attractive forces.

Question 20

A chemist is designing a process to maximize the solubility of sulfur dioxide ($$\mathrm{SO_2$}) in $$water. Which conditions should they use?

Accepted Answer

Low temperature and high pressure

Solutions: Types, Solubility, and Influencing Factors

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