Q: Which of the following is the correct formula for calculating molality ($$m$$)?

$$m = \frac{\text{mol of solute}}{\text{kg of solvent}}$$

Question 1

Which of the following best describes the process of solution formation in terms of enthalpy changes?

Accepted Answer

$$\Delta H_{soln} = \Delta H_1$ + \Delta H_2$ + \Delta H_3$, where $$\Delta $$H_1 is $$the separation of solute particles, $$\Delta H_2$ is the separation of solvent particles, and $$\Delta $$H_3 is $$the formation of solute-solvent interactions.

Question 2

A solution is made by dissolving 18.0 g of glucose ($$C_6H_{12}O_6$) in 100 g of water. The density of the solution is 1.03 g/mL. What is the molarity of the solution?

Accepted Answer

$$0.870\ M$$

Question 3

Which of the following statements about solubility is correct?

Accepted Answer

The solubility of a gas in a liquid increases with increasing pressure, as described by Henry's Law: $$S_g = kP_g.$$

Question 4

Which of the following pairs of substances are most likely to be miscible?

Accepted Answer

Methanol ($$CH_3OH) $$and water

Question 5

A 3.5 g sample of groundwater contains 2.5 $$\mug of$$ $$Pb^{2+}. $$What is the concentration of $$Pb^{2+} in $$parts per billion (ppb)?

Accepted Answer

$$694\ ppb$$

Question 6

Which of the following best explains why $$NaCl$$ dissolves in water?

Accepted Answer

The ion-dipole interactions between $$Na^+$$/$$Cl^-$$ and water are strong enough to overcome the lattice energy of $$NaCl.$$

Question 7

Which of the following solutions will produce the largest increase in boiling point when added to 1 kg of water?

Accepted Answer

2 mol $$KCl$$

Question 8

A solution is prepared by dissolving 4.60 g of ethanol ($$C_2H_5OH) in 500 g of $$water. The final volume of the solution is 515 mL. What is the molality of the solution?

Accepted Answer

$$0.199\ m$$

Question 9

Which equation correctly expresses Raoult’s Law for vapor pressure lowering?

Accepted Answer

$$P_A = X_A P_A^\circ$$

Question 10

A solution containing 1.50 g ethylene glycol ($$C_2H_6O_2) in 50.0 mL of $$solution at 25°C has what osmotic pressure? ($$R = 0.08206 L$$·atm/mol·K)

Accepted Answer

$$11.84\ atm$$

Question 11

Which of the following best describes a hypertonic solution with respect to a red blood cell?

Accepted Answer

The solute concentration outside the cell is greater than inside, causing water to flow out and the cell to crenate.

Question 12

Which of the following is NOT a colligative property?

Accepted Answer

Color of the solution

Question 13

A solution is made by dissolving 15.0 g of $$NaCl in 250 g of $$water. What is the mole fraction of water in the solution? ($$M_{NaCl} = 58.5 g/$$mol, $$M_{H_2O} = 18 g/$$mol)

Accepted Answer

$$0.989$$

Question 14

Which of the following statements about the effect of temperature on solubility is correct?

Accepted Answer

The solubility of gases in liquids decreases with increasing temperature.

Question 15

Calculate the freezing point of a solution made by dissolving 50.0 g of glucose ($$C_6H_{12}O_6$) in 500 g of water. (K_f = 1.86$$\ ^\circ C/m$$, M$$_{C_6H_{12}$$O_6$$} = 180$ g/mol)

Accepted Answer

$$-1.03\ ^\circ C$$

Question 16

Which of the following best describes an isotonic solution with respect to a cell?

Accepted Answer

The osmotic pressure is the same on both sides of the membrane, resulting in no net movement of water.

Question 17

Which of the following is the correct formula for calculating molality ($$m$$)?

Accepted Answer

$$m = \frac{	ext{mol of solute}}{	ext{kg of solvent}}$$

Question 18

Which of the following best explains why cyclohexane ($$C_6H_{12}) is $$essentially insoluble in water?

Accepted Answer

Cyclohexane is nonpolar and cannot form hydrogen bonds with water.

Question 19

A solution is made by dissolving 2.50 g of glucose ($$C_6H_{12}O_6$) in 250 g of water. What is the molality of the solution? (M$$_{C_6H_{12}$$O_6$$} = 180$ g/mol)

Accepted Answer

$$0.0556\ m$$

Properties of Solutions: Structure, Formation, and Colligative Effects

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