Q: Which of the following equations correctly relates the rate of effusion of two gases (A and B) to their molar masses according to Graham’s Law?

$\dfrac{\text{Rate}_A}{\text{Rate}_B} = \sqrt{\dfrac{M_B}{M_A}}$

Question 1

A scuba diver descends to a depth where the pressure is 3 atm. If the diver's lungs have a volume of 6.0 L at the surface (1 atm), what will be the volume of the diver's lungs at this depth, assuming temperature and amount of gas remain constant? (Use Boyle's Law.)

Accepted Answer

$2.0\ \mathrm{L}$

Question 2

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

Accepted Answer

The number of gas particles per unit volume decreases with altitude.

Question 3

A 10.0 L container holds 0.500 mol of an ideal gas at 300 K. What is the pressure inside the container? (Use $R = 0.08206\ \mathrm{L\cdot atm/(mol\cdot K)}$)

Accepted Answer

$1.23\ \mathrm{atm}$

Question 4

Which of the following statements about the kinetic molecular theory is FALSE?

Accepted Answer

Gas particles lose energy when they collide with each other.

Question 5

A sample of gas occupies 4.00 L at 27°C and 1.00 atm. What volume will it occupy at 127°C and 1.00 atm? (Use Charles’s Law.)

Accepted Answer

$5.33\ \mathrm{L}$

Question 6

Which device is used to measure the pressure of a gas in a closed container relative to atmospheric pressure?

Accepted Answer

Manometer

Question 7

A 5.00 L flask contains a mixture of nitrogen and oxygen gases at a total pressure of 2.00 atm. If the partial pressure of nitrogen is 1.50 atm, what is the mole fraction of oxygen in the mixture?

Accepted Answer

$0.25$

Question 8

Which of the following changes will increase the density of a gas, assuming the amount of gas remains constant?

Accepted Answer

Decreasing the temperature while keeping pressure constant

Question 9

A 12.5-L scuba tank contains 24.2 g of He and 4.32 g of O$_2$ at 298 K. What is the total pressure in the tank? ($R = 0.08206\ \mathrm{L\cdot atm/(mol\cdot K)}$; He: 4.00 g/mol, O$_2$: 32.00 g/mol)

Accepted Answer

$4.13\ \mathrm{atm}$

Question 10

Which of the following best describes why real gases deviate from ideal behavior at high pressures?

Accepted Answer

The volume of gas particles becomes significant compared to the container volume.

Question 11

A gas sample is collected over water at 25°C and a total pressure of 755 mmHg. If the vapor pressure of water at 25°C is 24 mmHg, what is the partial pressure of the dry gas?

Accepted Answer

$731\ \mathrm{mmHg}$

Question 12

Which of the following equations correctly relates the rate of effusion of two gases (A and B) to their molar masses according to Graham’s Law?

Accepted Answer

$\dfrac{	ext{Rate}_A}{	ext{Rate}_B} = \sqrt{\dfrac{M_B}{M_A}}$

Question 13

A sample of gas has a density of $1.96\ \mathrm{g/L}$ at STP. What is the molar mass of the gas?

Accepted Answer

$43.9\ \mathrm{g/mol}$

Question 14

Which of the following is a direct consequence of the kinetic molecular theory for gases?

Accepted Answer

The average kinetic energy of gas particles is proportional to the absolute temperature.

Question 15

A 2.00 L sample of gas at 300 K and 1.00 atm is compressed to 1.00 L at constant temperature. What is the final pressure?

Accepted Answer

$2.00\ \mathrm{atm}$

Question 16

Which of the following is NOT an assumption of the kinetic molecular theory?

Accepted Answer

Gas particles are strongly attracted to each other.

Question 17

A 1.00 mol sample of an ideal gas occupies 22.4 L at STP. If the temperature is doubled and the pressure is halved, what will be the new volume?

Accepted Answer

$89.6\ \mathrm{L}$

Question 18

Which of the following best describes the effect of intermolecular attractions on real gases at low temperatures?

Accepted Answer

The measured pressure is lower than predicted by the ideal gas law.

Chapter 10: Gases – Properties, Laws, and Applications

Study Guide - Practice Questions

Study Guide - Flashcards