Question 1

Which of the following substances exhibits hydrogen bonding as its strongest intermolecular force?

Accepted Answer

Methanol ($$\mathrm{CH_3OH})$$

Question 2

A sample of water at $$25^\circ\mathrm{C}$$ has a surface tension much higher than that of hexane at the same temperature. Which statement best explains this observation?

Accepted Answer

Water molecules form strong hydrogen bonds, requiring more energy to break through the surface.

Question 3

Which of the following best describes the relationship between vapor pressure and boiling point for a liquid?

Accepted Answer

A liquid boils when its vapor pressure equals atmospheric pressure.

Question 4

The Clausius–Clapeyron equation relates vapor pressure and temperature. Which of the following is the correct form of this equation?

Accepted Answer

$$\ln P = -\frac{\Delta H_{\mathrm{vap}}}{R} \cdot \frac{1}{T} + C$$

Question 5

Which of the following statements about crystalline solids is correct?

Accepted Answer

Crystalline solids have a repeating, ordered arrangement of particles called a lattice.

Question 6

A face-centered cubic (FCC) unit cell contains how many atoms per unit cell?

Accepted Answer

4

Question 7

Which of the following best explains why sodium chloride ($$\mathrm{NaCl}) is a $$good conductor of electricity when molten but not when solid?

Accepted Answer

In the solid state, ions are fixed in place and cannot move to conduct electricity.

Question 8

Which of the following is a network covalent solid?

Accepted Answer

Diamond ($$\mathrm{C})$$

Question 9

Which of the following statements about semiconductors is true?

Accepted Answer

Semiconductors have a small energy gap between the valence and conduction bands.

Question 10

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$glucose ($$\mathrm{C_6H_{12}O_6$}$$, molar mass $$180\ \mathrm{g/mol}) in$$ $$90.0\ \mathrm{g} of $$water. What is the molality of the solution?

Accepted Answer

$$0.556\ \mathrm{mol/kg}$$

Question 11

Which of the following best describes a saturated solution?

Accepted Answer

A solution in which no more solute can dissolve at a given temperature.

Question 12

Which of the following will increase the solubility of a gas in a liquid solvent?

Accepted Answer

Increasing the pressure of the gas above the solution.

Question 13

A $$0.10\ \mathrm{mol/L}$$ solution of sodium chloride ($$\mathrm{NaCl}) is $$prepared. Assuming complete dissociation, what is the expected van’t Hoff factor ($$i) $$for this solution?

Accepted Answer

$$i = 2$$

Question 14

Which of the following equations correctly expresses Raoult’s law for the vapor pressure of a solvent in an ideal solution?

Accepted Answer

$$P_{\mathrm{solution}} = X_{\mathrm{solvent}} P^0$_{\mathrm{solvent}}$$

Question 15

A $$0.20\ \mathrm{mol/kg}$$ aqueous solution of a nonvolatile, nonelectrolyte solute is prepared. If the freezing point depression constant for water is $$K_f = 1.86\ ^\circ\mathrm{C}\cdot\mathrm{kg}/\mathrm{mol}$$, what is the expected freezing point of the solution?

Accepted Answer

$$-0.372\ ^\circ\mathrm{C}$$

Question 16

Which of the following best explains why adding salt to ice causes the ice to melt at a lower temperature?

Accepted Answer

The salt lowers the freezing point of water by disrupting the equilibrium between solid and liquid phases.

Question 17

A $$0.50\ \mathrm{mol/L}$$ solution of a protein has an osmotic pressure of $$2.45\ \mathrm{atm} at$$ $$25^\circ\mathrm{C}. $$What is the molar mass of the protein? ($$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$4.99 	imes 10^4$\ \mathrm{g/mol}$$

Question 18

Which of the following statements about molarity and molality is correct?

Accepted Answer

Molarity depends on the volume of solution, while molality depends on the mass of solvent.

Question 19

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

Accepted Answer

The solubility increases as temperature increases.

Question 20

A sample of $$2.00\ \mathrm{g} of a $$nonvolatile solute is dissolved in $$100.0\ \mathrm{g} of $$water, lowering the vapor pressure of water from $$23.8\ \mathrm{mmHg} to$$ $$23.1\ \mathrm{mmHg} at$$ $$25^\circ\mathrm{C}. $$What is the mole fraction of the solute?

Accepted Answer

$$0.0294$$

Gases, Liquids, Solids, and Solutions: Intermolecular Forces, Phase Changes, and Solution Properties

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