Ion-dipole attractions between Na\textsuperscript{+}/Cl\textsuperscript{–} ions and water molecules.

$$\frac{10.0}{100.0} \times 100\% = 10.0\%$$

$$\frac{5.0\ \text{g}}{250\ \text{mL}} \times 100\% = 2.0\%$$

$$\text{NaCl}(s) \xrightarrow{H_2O} \text{Na}^+(aq) + \text{Cl}^-(aq)$$

Question 1

Which of the following best describes a solution?

Accepted Answer

A homogeneous mixture of two or more substances.

Question 2

When table salt (NaCl) dissolves in water, what is the primary interaction that allows the ions to separate?

Accepted Answer

Ion-dipole attractions between Na	extsuperscript{+}/Cl	extsuperscript{–} ions and water molecules.

Question 3

Which of the following statements about electrolytes is correct?

Accepted Answer

Strong electrolytes completely dissociate into ions in water.

Question 4

A solution is prepared by dissolving 10.0 g of KCl in 90.0 g of water. What is the mass percent (m/m) of KCl in the solution?

Accepted Answer

$$\frac{10.0}{100.0} 	imes 100\% = 10.0\%$$

Question 5

Which of the following best explains why oil does not dissolve in water?

Accepted Answer

Oil is nonpolar and water is polar, so there are no significant attractive forces between them.

Question 6

Which of the following solutions will conduct electricity the best?

Accepted Answer

A solution of sodium chloride (NaCl) in water.

Question 7

A 250 mL solution contains 5.0 g of KI. What is the mass/volume percent (m/v) of KI in the solution?

Accepted Answer

$$\frac{5.0\ 	ext{g}}{250\ 	ext{mL}} 	imes 100\% = 2.0\%$$

Question 8

Which of the following is a correct representation of the dissociation of NaCl in water?

Accepted Answer

$$	ext{NaCl}(s) \xrightarrow{H_2O} 	ext{Na}^+(aq) + 	ext{Cl}^-(aq)$$

Question 9

A solution is saturated when:

Accepted Answer

No more solute can dissolve and undissolved solute is present.

Question 10

Which of the following will increase the solubility of a solid solute in water?

Accepted Answer

Increasing the temperature of the solution.

Question 11

What is the molarity of a solution prepared by dissolving 60.0 g of NaOH (molar mass = 40.0 g/mol) in enough water to make 0.250 L of solution?

Accepted Answer

$$\frac{60.0\ 	ext{g}}{40.0\ 	ext{g/mol}} = 1.5\ 	ext{mol}$$; $$\frac{1.5\ 	ext{mol}}{0.250\ 	ext{L}} = 6.0\ 	ext{M}$$

Question 12

Which of the following best describes a weak electrolyte?

Accepted Answer

A substance that produces mostly molecules and a few ions in water.

Question 13

A hospital IV bag contains 5% (m/v) glucose solution. How many grams of glucose are in 500 mL of this solution?

Accepted Answer

$$5\% = 5\ 	ext{g}/100\ 	ext{mL};\ 5\ 	ext{g} 	imes 5 = 25\ 	ext{g}$$

Question 14

Which of the following is true about the effect of temperature on the solubility of gases in water?

Accepted Answer

Solubility of gases decreases as temperature increases.

Question 15

A solution is prepared by diluting 50.0 mL of a 6.0 M HCl solution to a final volume of 300.0 mL. What is the final concentration?

Accepted Answer

$$C_1V_1 = C_2V_2;\ (6.0\ 	ext{M})(50.0\ 	ext{mL}) = C_2$(300.0\ 	ext{mL});\ C_2$ = 1.0\ 	ext{M}$$

Question 16

Which of the following is a nonelectrolyte?

Accepted Answer

C$$_6H$_{12}O$_6 ($$glucose)

Question 17

A topical ointment contains 3.5% (m/m) neomycin. How many grams of neomycin are in a 64 g tube?

Accepted Answer

$$64\ 	ext{g} 	imes 0.035 = 2.24\ 	ext{g}$$

Question 18

Which of the following best describes the process of dilution?

Accepted Answer

Adding solvent to a solution, increasing volume and decreasing concentration.

chem exam 4 (ch12)-Solutions: Properties, Types, and Concentrations

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