Q: A sample of nitrogen gas is contained in a 10.0 L container at 2.0 atm. If the volume is decreased to 5.0 L at constant temperature, what will the new pressure be?

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{2.0\ \text{atm} \times 10.0\ \text{L}}{5.0\ \text{L}} = 4.0\ \text{atm}$$

Q: A gas has a pressure of 500 mmHg at 27°C. What will the pressure be at 127°C, assuming constant volume and amount of gas?

$$P_2$$ = $$P_1$$ \times \frac{$$T_2$$}{$$T_1$$} = 500\ \text{mmHg} \times \frac{400\ \text{K}}{300\ \text{K}} = 667\ \text{mmHg}$$

Q: A sample of helium gas occupies 250 mL at 25°C. What volume will it occupy at 75°C, assuming constant pressure?

$$V_2$$ = $$V_1$$ \times \frac{$$T_2$$}{$$T_1$$} = 250\ \text{mL} \times \frac{348\ \text{K}}{298\ \text{K}} = 292\ \text{mL}$$

Q: A 3.0 L sample of gas at 1.5 atm is compressed to 1.0 L at constant temperature. What is the final pressure?

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{1.5\ \text{atm} \times 3.0\ \text{L}}{1.0\ \text{L}} = 4.5\ \text{atm}$$

Q: A gas sample has a volume of 500 mL at 20°C. At what temperature (in °C) will the volume be 750 mL, assuming constant pressure?

$$T_2$$ = $$T_1$$ \times \frac{$$V_2$$}{$$V_1$$} = 293\ \text{K} \times \frac{750\ \text{mL}}{500\ \text{mL}} = 439.5\ \text{K} = 166.5^\circ \text{C}$$

Q: Which of the following is a correct conversion for atmospheric pressure?

$$1\ \text{atm} = 760\ \text{mmHg}$$

Q: A gas exerts a pressure of 2.5 atm in a 4.0 L container. If the pressure is reduced to 1.0 atm at constant temperature, what is the new volume?

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{2.5\ \text{atm} \times 4.0\ \text{L}}{1.0\ \text{atm}} = 10.0\ \text{L}$$

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 total volume of the gas.

Question 2

A sample of nitrogen gas is contained in a 10.0 L container at 2.0 atm. If the volume is decreased to 5.0 L at constant temperature, what will the new pressure be?

Accepted Answer

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{2.0\ 	ext{atm} 	imes 10.0\ 	ext{L}}{5.0\ 	ext{L}} = 4.0\ 	ext{atm}$$

Question 3

Which of the following best describes what happens to the pressure of a gas if its temperature is doubled (in Kelvin) while the volume and amount of gas remain constant?

Accepted Answer

The pressure is doubled.

Question 4

A gas has a pressure of 500 mmHg at 27°C. What will the pressure be at 127°C, assuming constant volume and amount of gas?

Accepted Answer

$$P_2$$ = $$P_1$$ 	imes \frac{$$T_2$$}{$$T_1$$} = 500\ 	ext{mmHg} 	imes \frac{400\ 	ext{K}}{300\ 	ext{K}} = 667\ 	ext{mmHg}$$

Question 5

Which of the following is NOT a property used to describe a gas?

Accepted Answer

Density

Question 6

A sample of helium gas occupies 250 mL at 25°C. What volume will it occupy at 75°C, assuming constant pressure?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$T_2$$}{$$T_1$$} = 250\ 	ext{mL} 	imes \frac{348\ 	ext{K}}{298\ 	ext{K}} = 292\ 	ext{mL}$$

Question 7

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

Accepted Answer

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

Question 8

Which of the following units is NOT commonly used to measure gas pressure?

Accepted Answer

Joule (J)

Question 9

A 3.0 L sample of gas at 1.5 atm is compressed to 1.0 L at constant temperature. What is the final pressure?

Accepted Answer

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{1.5\ 	ext{atm} 	imes 3.0\ 	ext{L}}{1.0\ 	ext{L}} = 4.5\ 	ext{atm}$$

Question 10

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

Accepted Answer

Average kinetic energy is directly proportional to the Kelvin temperature.

Question 11

A gas sample has a volume of 500 mL at 20°C. At what temperature (in °C) will the volume be 750 mL, assuming constant pressure?

Accepted Answer

$$T_2$$ = $$T_1$$ 	imes \frac{$$V_2$$}{$$V_1$$} = 293\ 	ext{K} 	imes \frac{750\ 	ext{mL}}{500\ 	ext{mL}} = 439.5\ 	ext{K} = 166.5^\circ 	ext{C}$$

Question 12

Which of the following is a correct conversion for atmospheric pressure?

Accepted Answer

$$1\ 	ext{atm} = 760\ 	ext{mmHg}$$

Question 13

A gas exerts a pressure of 2.5 atm in a 4.0 L container. If the pressure is reduced to 1.0 atm at constant temperature, what is the new volume?

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{2.5\ 	ext{atm} 	imes 4.0\ 	ext{L}}{1.0\ 	ext{atm}} = 10.0\ 	ext{L}$$

Question 14

Which of the following scenarios best illustrates Boyle’s Law?

Accepted Answer

A syringe plunger is pushed in, decreasing the volume and increasing the pressure of the gas inside.

Question 15

If a gas sample is heated from 300 K to 600 K at constant pressure, what happens to its volume?

Accepted Answer

The volume doubles.

Question 16

Which of the following best explains why atmospheric pressure decreases with altitude?

Accepted Answer

There are fewer gas particles in the air at higher altitudes.

Gas Laws and Properties: Kinetic Molecular Theory, Boyle’s, Charles’s, and Gay-Lussac’s Laws

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