Q: A sample of gas occupies 2.50 L at 760 mm Hg. If the pressure is decreased to 630 mm Hg at constant temperature, what will be the new volume?

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{(760\ \text{mm Hg})(2.50\ \text{L})}{630\ \text{mm Hg}} = 3.02\ \text{L}$$

Q: Which of the following correctly expresses Dalton’s Law of Partial Pressures?

$$P_{\text{total}} = P_1$ + P_2$ + P_3$ + \ldots$$

Q: Which of the following is the correct value of the gas constant $$R$$ when pressure is in atm and volume is in liters?

$$R = 0.0821\ \text{L·atm·mol}^{-1}\text{·K}^{-1}$$

Question 1

Which of the following statements best describes the kinetic-molecular theory of gases?

Accepted Answer

Gas particles are in constant, random motion and their collisions with the walls of the container cause pressure.

Question 2

A sample of gas occupies 2.50 L at 760 mm Hg. If the pressure is decreased to 630 mm Hg at constant temperature, what will be the new volume?

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{(760\ 	ext{mm Hg})(2.50\ 	ext{L})}{630\ 	ext{mm Hg}} = 3.02\ 	ext{L}$$

Question 3

Which of the following is NOT an assumption of the kinetic-molecular theory for ideal gases?

Accepted Answer

Gas particles exert attractive and repulsive forces on each other.

Question 4

A hot air balloon rises because:

Accepted Answer

Heating the air inside the balloon decreases its density, causing it to rise.

Question 5

Which of the following correctly expresses Dalton’s Law of Partial Pressures?

Accepted Answer

$$P_{	ext{total}} = P_1$ + P_2$ + P_3$ + \ldots$$

Question 6

A mixture of 6.00 g O$$_2$$ and 9.00 g CH$$_4 is $$placed in a 0.015 m$$^3$$ vessel at 0$$^	ext{o}C. $$What is the total pressure in the vessel? (Use $$R = 8.314 m$^3$$·Pa·mol$$^{-1}$$·K$$^{-1})$$

Accepted Answer

$$P_t = 113.64\ 	ext{kPa}$$

Question 7

Which of the following is the correct form of the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 8

If the temperature of a fixed amount of gas is doubled at constant pressure, what happens to its volume?

Accepted Answer

The volume doubles.

Question 9

A 250 mL flask contains CO$$_2$$ gas at 131.72 kPa and 31$$^	ext{o}C. $$How many moles of CO$$_2$$ are present? (Use $$R = 8.314 L$$·kPa·mol$$^{-1}$$·K$$^{-1})$$

Accepted Answer

$$n = 0.013\ 	ext{mol}$$

Question 10

Which of the following is a correct conversion for 1 atm of pressure?

Accepted Answer

1 atm = 101.325 kPa

Question 11

A gas sample has a volume of 20.0 L at 5$$^	ext{o}C $$and 730 torr. What will be its volume at 50.0$$^	ext{o}C $$and 800 torr?

Accepted Answer

$$V_2 = 21.2$$\ 	ext{L}$$

Question 12

Which of the following best explains why gases are compressible?

Accepted Answer

Gas particles are far apart compared to their size.

Question 13

Which law states that the volume of a gas is directly proportional to the number of moles at constant temperature and pressure?

Accepted Answer

Avogadro’s Law

Question 14

A mercury barometer is used to measure atmospheric pressure. If the atmospheric pressure increases, what happens to the height $$h of $$the mercury column?

Accepted Answer

The height $$h$$ increases.

Question 15

Which of the following is the correct value of the gas constant $$R$$ when pressure is in atm and volume is in liters?

Accepted Answer

$$R = 0.0821\ 	ext{L·atm·mol}^{-1}	ext{·K}^{-1}$$

Question 16

Which of the following best describes the relationship between pressure and volume for a fixed amount of gas at constant temperature?

Accepted Answer

Pressure is inversely proportional to volume.

The Gaseous State of Matter: Properties, Laws, and Applications

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