Q: A sample of gas occupies 1.7 L at a pressure of 1.2 atm. If the pressure is increased to 1.5 atm at constant temperature, what will be the new volume of the gas? (Assume ideal gas behavior.)

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{1.2 \times 1.7}{1.5} = 1.36\ \text{L}$$

Q: If 1.7 L of a gas at 298 K is heated to 350 K at constant pressure, what is the new volume?

$$V_2$$ = $$V_1$$ \frac{$$T_2$$}{$$T_1$$} = 1.7 \times \frac{350}{298} = 2.0\ \text{L}$$

Q: When 14.2 g of Zn reacts with excess HCl according to $$\mathrm{Zn\ (s) + 2HCl\ (aq) \rightarrow H_2$\ (g) + $$ZnCl_2$$\ (aq)}$$, what is the volume of hydrogen gas produced at 298 K and 1 atm? (Molar mass Zn = 65.4 g/mol, $$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

$$n_{Zn} = \frac{14.2}{65.4} = 0.217\ \text{mol}$$; $$n_{H_2$} = 0.217\ \text{mol}$$; $$V = nRT/P = 0.217 \times 0.0821 \times 298 / 1 = 5.30\ \text{L}$$

Q: What is the molarity of a solution made by dissolving 11 g of NaCl in enough water to make 32 L of solution? (Molar mass NaCl = 58.44 g/mol)

$$M = \frac{\text{moles}}{\text{liters}} = \frac{11/58.44}{32} = 0.0059\ \text{M}$$

Q: If 11 g of NaCl is dissolved in 32 L of water, what is the concentration in percent by mass? (Assume density of water is 1.00 g/mL.)

$$\%\ \text{by mass} = \frac{11}{11 + 32000} \times 100 = 0.034\%$$

Question 1

A sample of gas occupies 1.7 L at a pressure of 1.2 atm. If the pressure is increased to 1.5 atm at constant temperature, what will be the new volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{1.2 	imes 1.7}{1.5} = 1.36\ 	ext{L}$$

Question 2

If 1.7 L of a gas at 298 K is heated to 350 K at constant pressure, what is the new volume?

Accepted Answer

$$V_2$$ = $$V_1$$ \frac{$$T_2$$}{$$T_1$$} = 1.7 	imes \frac{350}{298} = 2.0\ 	ext{L}$$

Question 3

A 1.7 L sample of gas is at 298 K and 1.2 atm. What will the volume be if the temperature is increased to 400 K and the pressure is increased to 2.1 atm?

Accepted Answer

$$V_2$$ = $$V_1$$ \frac{$$T_2$$}{$$T_1$$} \frac{$$P_1$$}{$$P_2$$} = 1.7 	imes \frac{400}{298} 	imes \frac{1.2}{2.1} = 1.1\ 	ext{L}$$

Question 4

When 14.2 g of Zn reacts with excess HCl according to $$\mathrm{Zn\ (s) + 2HCl\ (aq) \rightarrow H_2$\ (g) + $$ZnCl_2$$\ (aq)}$$, what is the volume of hydrogen gas produced at 298 K and 1 atm? (Molar mass Zn = 65.4 g/mol, $$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$n_{Zn} = \frac{14.2}{65.4} = 0.217\ 	ext{mol}$$; $$n_{H_2$} = 0.217\ 	ext{mol}$$; $$V = nRT/P = 0.217 	imes 0.0821 	imes 298 / 1 = 5.30\ 	ext{L}$$

Question 5

Which of the following best describes what happens to gas particles as they are warmed from absolute zero?

Accepted Answer

They move faster and their kinetic energy increases.

Question 6

How do gas particles exert pressure on the walls of a container?

Accepted Answer

By colliding with the walls and transferring momentum.

Question 7

Which statement best compares the spacing of gas particles to those in liquids and solids?

Accepted Answer

Gas particles are much farther apart than those in liquids or solids.

Question 8

What is the molarity of a solution made by dissolving 11 g of NaCl in enough water to make 32 L of solution? (Molar mass NaCl = 58.44 g/mol)

Accepted Answer

$$M = \frac{	ext{moles}}{	ext{liters}} = \frac{11/58.44}{32} = 0.0059\ 	ext{M}$$

Question 9

If 11 g of NaCl is dissolved in 32 L of water, what is the concentration in percent by mass? (Assume density of water is 1.00 g/mL.)

Accepted Answer

$$\%\ 	ext{by mass} = \frac{11}{11 + 32000} 	imes 100 = 0.034\%$$

Question 10

In a town with hard water, the concentration of calcium carbonate is 120 ppm. If you boil a liter of tap water to dryness, how many milligrams of calcium carbonate would remain?

Accepted Answer

$$120\ 	ext{mg}$$

Question 11

How many mL of a 12 M HCl solution should be diluted to make 1200 mL of a 3.0 M HCl solution?

Accepted Answer

$$M_1$$ $$V_1$$ = $$M_2$$ $$V_2$$ \implies $$V_1$$ = \frac{$$M_2$$ $$V_2$$}{$$M_1$$} = \frac{3.0 	imes 1200}{12} = 300\ 	ext{mL}$$

Question 12

Which term describes a solution that has absorbed all the solute it can at a given temperature?

Accepted Answer

Saturated

Question 13

Does hot water dissolve solids better or worse than cold water?

Accepted Answer

Better

Question 14

Does hot water dissolve gases better or worse than cold water?

Accepted Answer

Worse

Question 15

Which of the following is an Arrhenius acid?

Accepted Answer

A substance that increases $$[H^+] in $$aqueous solution

Question 16

Which of the following is a Bronsted-Lowry base?

Accepted Answer

A substance that accepts a proton ($$H^+)$$

Question 17

For the reaction $$\mathrm{H_3AsO_4\ (aq) + H_2O\ (l) \rightleftharpoons H_3O^+\ (aq) + H_2AsO_4^-\ (aq)}$$, which species is the conjugate base?

Accepted Answer

$$\mathrm{H_2AsO_4^-}$$

Question 18

What is the difference between a strong acid and a weak acid?

Accepted Answer

A strong acid completely ionizes in water, while a weak acid only partially ionizes.

Question 19

If $$[H_3O^+] = 0.0023\ \mathrm{M}$$, what is the pH of the solution?

Accepted Answer

$$\mathrm{pH} = -\log_{10}(0.0023) = 2.64$$

CHEM1101 Chapters 11–14 Review: Step-by-Step Study Guidance

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