Q: A sample of nitrogen gas occupies a volume of 8.0 L at a pressure of 2.0 atm. If the pressure is decreased to 1.0 atm at constant temperature and amount, what will be the new volume?

$$V_2$$ = \frac{P_1V_1}{$$P_2$$} = \frac{2.0\,\text{atm} \times 8.0\,\text{L}}{1.0\,\text{atm}} = 16.0\,\text{L}$$

Q: A gas sample has a pressure of 750 mmHg. What is this pressure in atmospheres?

$$P = \frac{750\,\text{mmHg}}{760\,\text{mmHg/atm}} = 0.987\,\text{atm}$$

Q: A balloon filled with helium has a volume of 500 mL at 25°C. If the temperature increases to 75°C at constant pressure, what is the new volume? (Use Charles’s Law)

$$V_2$$ = $$V_1$$ \times \frac{$$T_2$$}{$$T_1$$} = 500\,\text{mL} \times \frac{348\,\text{K}}{298\,\text{K}} = 584\,\text{mL}$$

Q: A sample of gas at 300 K exerts a pressure of 1.5 atm. If the temperature is increased to 600 K at constant volume, what is the new pressure?

$$P_2$$ = $$P_1$$ \times \frac{$$T_2$$}{$$T_1$$} = 1.5\,\text{atm} \times \frac{600\,\text{K}}{300\,\text{K}} = 3.0\,\text{atm}$$

Q: A sample of oxygen gas has a volume of 12.0 L at a pressure of 600 mmHg. What is the final pressure when the volume changes to 36.0 L at constant temperature and amount?

$$P_2$$ = \frac{P_1V_1}{$$V_2$$} = \frac{600\,\text{mmHg} \times 12.0\,\text{L}}{36.0\,\text{L}} = 200\,\text{mmHg}$$

Q: A gas has a pressure of 645 Torr at 128°C. What is the temperature in °C if the pressure increases to 824 Torr (V and n constant)?

$$T_2$$ = $$T_1$$ \times \frac{$$P_2$$}{$$P_1$$} = 401\,\text{K} \times \frac{824}{645} = 513\,\text{K};\ $$T_2 = 513 - 273 = 240$$^\circ\text{C}$$

Question 1

According to the Kinetic Molecular Theory, which of the following statements best explains why gases are easily compressed?

Accepted Answer

The actual volume occupied by gas molecules is extremely small compared to the volume the gas occupies.

Question 2

A sample of nitrogen gas occupies a volume of 8.0 L at a pressure of 2.0 atm. If the pressure is decreased to 1.0 atm at constant temperature and amount, what will be the new volume?

Accepted Answer

$$V_2$$ = \frac{P_1V_1}{$$P_2$$} = \frac{2.0\,	ext{atm} 	imes 8.0\,	ext{L}}{1.0\,	ext{atm}} = 16.0\,	ext{L}$$

Question 3

Which of the following best describes the relationship between temperature and kinetic energy of gas particles?

Accepted Answer

The kinetic energy of gas particles is directly proportional to the Kelvin temperature.

Question 4

A gas sample has a pressure of 750 mmHg. What is this pressure in atmospheres?

Accepted Answer

$$P = \frac{750\,	ext{mmHg}}{760\,	ext{mmHg/atm}} = 0.987\,	ext{atm}$$

Question 5

A balloon filled with helium has a volume of 500 mL at 25°C. If the temperature increases to 75°C at constant pressure, what is the new volume? (Use Charles’s Law)

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$T_2$$}{$$T_1$$} = 500\,	ext{mL} 	imes \frac{348\,	ext{K}}{298\,	ext{K}} = 584\,	ext{mL}$$

Question 6

Which of the following is NOT a correct unit of pressure?

Accepted Answer

Joule

Question 7

A gas cylinder contains 3.0 moles of oxygen gas. If the amount of gas is doubled at constant volume and temperature, what happens to the pressure?

Accepted Answer

The pressure doubles.

Question 8

A sample of gas at 300 K exerts a pressure of 1.5 atm. If the temperature is increased to 600 K at constant volume, what is the new pressure?

Accepted Answer

$$P_2$$ = $$P_1$$ 	imes \frac{$$T_2$$}{$$T_1$$} = 1.5\,	ext{atm} 	imes \frac{600\,	ext{K}}{300\,	ext{K}} = 3.0\,	ext{atm}$$

Question 9

Why does water boil at a lower temperature in the mountains than at sea level?

Accepted Answer

Atmospheric pressure is lower in the mountains, so water's vapor pressure equals atmospheric pressure at a lower temperature.

Question 10

A sample of oxygen gas has a volume of 12.0 L at a pressure of 600 mmHg. What is the final pressure when the volume changes to 36.0 L at constant temperature and amount?

Accepted Answer

$$P_2$$ = \frac{P_1V_1}{$$V_2$$} = \frac{600\,	ext{mmHg} 	imes 12.0\,	ext{L}}{36.0\,	ext{L}} = 200\,	ext{mmHg}$$

Question 11

A gas has a pressure of 645 Torr at 128°C. What is the temperature in °C if the pressure increases to 824 Torr (V and n constant)?

Accepted Answer

$$T_2$$ = $$T_1$$ 	imes \frac{$$P_2$$}{$$P_1$$} = 401\,	ext{K} 	imes \frac{824}{645} = 513\,	ext{K};\ $$T_2 = 513 - 273 = 240$$^\circ	ext{C}$$

Question 12

Which of the following best explains why a gas exerts pressure on the walls of its container?

Accepted Answer

Gas particles collide with the walls of the container, transferring momentum.

Question 13

If a gas at 1.0 atm and 300 K is compressed from 4.0 L to 2.0 L at constant temperature, what is the final pressure?

Accepted Answer

$$P_2$$ = \frac{P_1V_1}{$$V_2$$} = \frac{1.0\,	ext{atm} 	imes 4.0\,	ext{L}}{2.0\,	ext{L}} = 2.0\,	ext{atm}$$

Question 14

Which property of a gas is most directly affected when the temperature is increased at constant volume and amount?

Accepted Answer

Pressure

Question 15

A weather balloon is released at sea level where the atmospheric pressure is 1 atm. As it rises to higher altitudes, what happens to the volume of the balloon (assuming constant temperature)?

Accepted Answer

The volume increases because atmospheric pressure decreases.

Gas Laws and Properties: Kinetic Molecular Theory and Fundamental Gas Laws

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