Q: A solution is prepared by dissolving 30.0 g of H$$_2SO$_4 ($$molar mass = 98.08 g/mol) in enough water to make 100.0 g of solution. If the density of the solution is 1.26 g/mL, what is the molality of H$$_2SO$_4 in $$the solution?

$$m = \frac{0.306}{0.070} = 4.37~\text{mol/kg}$$

Q: A 2.00 L bottle of soda is sealed under a CO$$_2$$ pressure of 2.05 atm at 25°C. Given $$k_{CO_2$} = 0.031~\text{mol}/(\text{L} \cdot \text{atm})$$, how many grams of CO$$_2$$ are dissolved in the soda?

$$n = 0.127~\text{mol}$$, $$m = 5.59~\text{g}$$

Q: What is the osmotic pressure (in atm) required to prevent the flow of pure water into seawater (1.13 mol/L total ions) at 25°C? ($$R = 0.0821~\text{L} \cdot \text{atm} \cdot \text{mol}^{-1} \cdot \text{K}^{-1})$$

$$\Pi = 1.13 \times 0.0821 \times 298 = 27.6~\text{atm}$$

Q: A 394 g sample of soda contains 39.0 g of sugar (C$$_{12}H$_{22}O$_{11}$$, molar mass = 342 g/mol). What is the mole fraction of sugar in the mixture if the rest is water (molar mass = 18.0 g/mol)?

$$\chi_{\text{sugar}} = \frac{0.114}{21.9} = 0.0052$$

Q: A solution is made by dissolving 50.0 mL of ethylene glycol (C$$_2H$_6O$_2$$, density = 1.113 g/mL) in 50.0 mL of water (density = 1.00 g/mL). What is the molality of ethylene glycol in the solution?

$$m = \frac{0.893}{0.050} = 17.9~\text{mol/kg}$$

Q: A 100.0 g sample of nitric acid solution is 68.0% HNO$$_3 by $$mass and has a density of 1.513 g/mL. What is the molarity of HNO$$_3 in $$the solution?

$$M = \frac{1.11~\text{mol}}{0.0661~\text{L}} = 16.8~\text{M}$$

Question 1

Which of the following best describes the solution formed when 4000 grams of sugar is dissolved in 1 L of water at 90°C and then cooled to 50°C?

Accepted Answer

Supersaturated

Question 2

A solution is prepared by dissolving 30.0 g of H$$_2SO$_4 ($$molar mass = 98.08 g/mol) in enough water to make 100.0 g of solution. If the density of the solution is 1.26 g/mL, what is the molality of H$$_2SO$_4 in $$the solution?

Accepted Answer

$$m = \frac{0.306}{0.070} = 4.37~	ext{mol/kg}$$

Question 3

Which intermolecular force is primarily responsible for the miscibility of water and ethanol?

Accepted Answer

Hydrogen bonding

Question 4

A 2.00 L bottle of soda is sealed under a CO$$_2$$ pressure of 2.05 atm at 25°C. Given $$k_{CO_2$} = 0.031~	ext{mol}/(	ext{L} \cdot 	ext{atm})$$, how many grams of CO$$_2$$ are dissolved in the soda?

Accepted Answer

$$n = 0.127~	ext{mol}$$, $$m = 5.59~	ext{g}$$

Question 5

Which of the following solutions will have the lowest freezing point? (Assume complete dissociation for ionic compounds.)

Accepted Answer

0.02 m MgCl$$_2$$

Question 6

What is the osmotic pressure (in atm) required to prevent the flow of pure water into seawater (1.13 mol/L total ions) at 25°C? ($$R = 0.0821~	ext{L} \cdot 	ext{atm} \cdot 	ext{mol}^{-1} \cdot 	ext{K}^{-1})$$

Accepted Answer

$$\Pi = 1.13 	imes 0.0821 	imes 298 = 27.6~	ext{atm}$$

Question 7

Which of the following best explains why gases dissolve less well in warm water than in cold water?

Accepted Answer

Gas molecules have higher kinetic energy and escape more easily from the solution.

Question 8

A 394 g sample of soda contains 39.0 g of sugar (C$$_{12}H$_{22}O$_{11}$$, molar mass = 342 g/mol). What is the mole fraction of sugar in the mixture if the rest is water (molar mass = 18.0 g/mol)?

Accepted Answer

$$\chi_{	ext{sugar}} = \frac{0.114}{21.9} = 0.0052$$

Question 9

Which of the following statements about colligative properties is correct?

Accepted Answer

They depend only on the number of solute particles.

Question 10

A solution is made by dissolving 50.0 mL of ethylene glycol (C$$_2H$_6O$_2$$, density = 1.113 g/mL) in 50.0 mL of water (density = 1.00 g/mL). What is the molality of ethylene glycol in the solution?

Accepted Answer

$$m = \frac{0.893}{0.050} = 17.9~	ext{mol/kg}$$

Question 11

Which of the following best describes what happens to a cell placed in a hypertonic solution?

Accepted Answer

The cell shrivels as water leaves.

Question 12

Which of the following aqueous solutions will have the highest boiling point? (Assume complete dissociation for ionic compounds.)

Accepted Answer

0.10 m K$$_2SO$_4$$

Question 13

A 100.0 g sample of nitric acid solution is 68.0% HNO$$_3 by $$mass and has a density of 1.513 g/mL. What is the molarity of HNO$$_3 in $$the solution?

Accepted Answer

$$M = \frac{1.11~	ext{mol}}{0.0661~	ext{L}} = 16.8~	ext{M}$$

Question 14

Which of the following best explains why the vapor pressure of a solvent decreases when a nonvolatile solute is added?

Accepted Answer

The solute particles occupy surface sites, reducing the number of solvent molecules that can escape.

Question 15

Which of the following is the correct van’t Hoff factor ($$i) $$for Na$$_2SO$_4 in $$water, assuming complete dissociation?

Accepted Answer

$$i = 3$$

Question 16

A solution is prepared by dissolving 33.0 g of KNO$$_3 ($$molar mass = 101 g/mol) in 200. mL of water. What is the boiling point of the solution? ($$K_b = 0.512~^\circ	ext{C}/m$$ for water)

Accepted Answer

$$\Delta T_b = 0.84~^\circ	ext{C}$$, 	ext{Boiling point} = 100.84~^\circ	ext{C}$

Question 17

Which of the following best describes the effect of adding a solute to a solvent on the solvent’s boiling point and freezing point?

Accepted Answer

Boiling point increases and freezing point decreases.

Chapter 13: Solutions and Colligative Properties – Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드