Q: A sample of oxygen gas has a volume of 12.0 L at a pressure of 600 mmHg. If the volume changes to 36.0 L at constant temperature and amount, what is the final pressure in mmHg? (Use Boyle’s Law: $$P_1V_1 = P_2V_2)$$

$$P_2$$ = \frac{P_1V_1}{$$V_2$$} = \frac{600 \times 12.0}{36.0} = 200$$ 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, assuming constant volume and amount? (Use Gay-Lussac’s Law: $$\frac{P_1$}{T_1$} = \frac{P_2$}{T_2$}$$, temperatures in Kelvin)

$$T_2$$ = \frac{$$P_2$$ \times $$T_1$$}{$$P_1$$} = \frac{824 \times 401}{645} = 513$$ K = 240°C

Q: A sample of oxygen gas has a volume of 420 mL at 18°C. At what temperature (in °C) will the volume be 640 mL, assuming constant pressure and amount? (Use Charles’s Law: $$\frac{V_1$}{T_1$} = \frac{V_2$}{T_2$}$$, temperatures in Kelvin)

$$T_2$$ = \frac{$$V_2$$ \times $$T_1$$}{$$V_1$$} = \frac{640 \times 291}{420} = 444$$ K = 171°C

Q: A rigid container holds a gas at 2.0 atm and 300 K. If the temperature increases to 600 K, what is the new pressure? (Use Gay-Lussac’s Law: $$\frac{P_1$}{T_1$} = \frac{P_2$}{T_2$})$$

$$P_2$$ = \frac{$$P_1$$ \times $$T_2$$}{$$T_1$$} = \frac{2.0 \times 600}{300} = 4.0$$ atm

Q: Which of the following is a correct equality for pressure units?

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

Q: A gas is compressed from 8.0 L to 2.0 L at constant temperature. If the initial pressure was 1.0 atm, what is the final pressure? (Use Boyle’s Law: $$P_1V_1 = P_2V_2)$$

$$P_2$$ = \frac{P_1V_1}{$$V_2$$} = \frac{1.0 \times 8.0}{2.0} = 4.0$$ atm

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 oxygen gas has a volume of 12.0 L at a pressure of 600 mmHg. If the volume changes to 36.0 L at constant temperature and amount, what is the final pressure in mmHg? (Use Boyle’s Law: $$P_1V_1 = P_2V_2)$$

Accepted Answer

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

Question 3

Which of the following best describes why water boils at a lower temperature in the mountains than at sea level?

Accepted Answer

The atmospheric pressure is lower at higher altitudes, so water molecules require less energy to escape into the gas phase.

Question 4

A gas has a pressure of 645 Torr at 128°C. What is the temperature in °C if the pressure increases to 824 Torr, assuming constant volume and amount? (Use Gay-Lussac’s Law: $$\frac{P_1$}{T_1$} = \frac{P_2$}{T_2$}$$, temperatures in Kelvin)

Accepted Answer

$$T_2$$ = \frac{$$P_2$$ 	imes $$T_1$$}{$$P_1$$} = \frac{824 	imes 401}{645} = 513$$ K = 240°C

Question 5

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

Accepted Answer

Density

Question 6

A sample of oxygen gas has a volume of 420 mL at 18°C. At what temperature (in °C) will the volume be 640 mL, assuming constant pressure and amount? (Use Charles’s Law: $$\frac{V_1$}{T_1$} = \frac{V_2$}{T_2$}$$, temperatures in Kelvin)

Accepted Answer

$$T_2$$ = \frac{$$V_2$$ 	imes $$T_1$$}{$$V_1$$} = \frac{640 	imes 291}{420} = 444$$ K = 171°C

Question 7

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

Accepted Answer

mL

Question 8

If the temperature of a gas is doubled (in Kelvin) at constant volume and amount, what happens to the pressure?

Accepted Answer

The pressure doubles.

Question 9

Which of the following best explains why a balloon expands when heated?

Accepted Answer

The gas particles move faster, increasing the pressure and causing the balloon to expand.

Question 10

A rigid container holds a gas at 2.0 atm and 300 K. If the temperature increases to 600 K, what is the new pressure? (Use Gay-Lussac’s Law: $$\frac{P_1$}{T_1$} = \frac{P_2$}{T_2$})$$

Accepted Answer

$$P_2$$ = \frac{$$P_1$$ 	imes $$T_2$$}{$$T_1$$} = \frac{2.0 	imes 600}{300} = 4.0$$ atm

Question 11

Which of the following is a correct equality for pressure units?

Accepted Answer

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

Question 12

A gas is compressed from 8.0 L to 2.0 L at constant temperature. If the initial pressure was 1.0 atm, what is the final pressure? (Use Boyle’s Law: $$P_1V_1 = P_2V_2)$$

Accepted Answer

$$P_2$$ = \frac{P_1V_1}{$$V_2$$} = \frac{1.0 	imes 8.0}{2.0} = 4.0$$ atm

Question 13

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

Accepted Answer

The average kinetic energy is proportional to the Kelvin temperature.

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

Which of the following is the correct formula for calculating pressure?

Accepted Answer

$$	ext{Pressure} = \frac{	ext{Force}}{	ext{Area}}$$

Gas Laws and the Behavior of Gases

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