Q: A can of soda contains 0.14 M CO$$_2 at 20$^\circC. $$Given $$k_H$$ for CO$$_2 is$$ $$3.5 \times 10$$^{-2}$$ mol/(L·atm), what is the partial pressure of CO_2$ required to keep the soda carbonated?

$$P_{CO_2$} = \frac{0.14}{3.5 \times 10$$^{-2}$$} = 4.0$$ atm

Question 1

Which of the following best explains why NaCl dissolves readily in water but not in hexane (C6H14)?

Accepted Answer

Water molecules form ion-dipole interactions with Na+ and Cl- ions, stabilizing them in solution.

Question 2

A solution contains 50 g of KNO$$_3 in 100 g of H$_2O at 50$^\circC. $$Based on the solubility curve, is this solution saturated, unsaturated, or supersaturated?

Accepted Answer

Saturated

Question 3

Which of the following statements about Henry's Law is correct?

Accepted Answer

The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.

Question 4

A can of soda contains 0.14 M CO$$_2 at 20$^\circC. $$Given $$k_H$$ for CO$$_2 is$$ $$3.5 	imes 10$$^{-2}$$ mol/(L·atm), what is the partial pressure of CO_2$ required to keep the soda carbonated?

Accepted Answer

$$P_{CO_2$} = \frac{0.14}{3.5 	imes 10$$^{-2}$$} = 4.0$$ atm

Question 5

Which process is endothermic during the dissolution of an ionic solid in water?

Accepted Answer

Breaking apart the solute into its constituent ions ($$\Delta H_{solute})$$

Question 6

Which of the following best describes a supersaturated solution?

Accepted Answer

A solution that contains more solute than is normally possible at a given temperature.

Question 7

Why does the solubility of gases in water decrease as temperature increases?

Accepted Answer

Increased temperature increases the vapor pressure of the gas, causing more gas to escape from the solution.

Question 8

Which of the following pairs will most likely form a miscible solution?

Accepted Answer

Ethanol (C$$_2H$_5OH) $$and water (H$$_2O)$$

Question 9

Which of the following best describes the energy changes during the dissolution process?

Accepted Answer

$$\Delta H_{soln} = \Delta H_{solute} + \Delta H_{solvent} + \Delta H_{mix}$$

Question 10

A student adds 10 g of KClO$$_3 to 100 g of $$water at 30$$^\circC. $$Based on the solubility curve, what type of solution is formed?

Accepted Answer

Unsaturated

Question 11

Which of the following is a real-life example of Henry's Law in action?

Accepted Answer

CO$$_2$$ escaping from a soda can when it is opened.

Question 12

If the enthalpy of solution ($$\Delta H_{soln}) is $$negative, what can you conclude about the temperature change of the surroundings?

Accepted Answer

The temperature of the surroundings increases.

Question 13

Which of the following best describes an unsaturated solution?

Accepted Answer

A solution that contains less solute than can be dissolved at a given temperature.

Question 14

Which of the following gases will have the highest solubility in water at 20$$^\circC$$, based on the given $$k_H$$ values?

Accepted Answer

CO$$_2$$ ($$k_H = 3.5 	imes 10$$^{-2}$$ mol/(L·atm))

Question 15

Which of the following is NOT a factor that affects the solubility of a solid in a liquid?

Accepted Answer

Color of the solute

Question 16

Which step in the solution process is always endothermic?

Accepted Answer

Separating solute particles ($$\Delta H_{solute})$$

Question 17

A solution is prepared by dissolving 80 g of NaNO$$_3 in 100 g of $$water at 30$$^\circC. $$According to the solubility curve, is this solution saturated, unsaturated, or supersaturated?

Accepted Answer

Supersaturated

Question 18

Which of the following best explains why oil and water do not mix?

Accepted Answer

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

Question 19

Which of the following is true about the enthalpy change when a solution forms?

Accepted Answer

If $$|\Delta H_{mix}| \u003e |\Delta H_{solute} + \Delta H_{solvent}|$$, the process is exothermic.

Chapter 14: Introduction to Solutions and Solubility

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