Question 1

A scuba diver descends to a depth where the pressure is 3.0 atm. If the diver inhales 2.0 L of air at the surface (1.0 atm), what will be the volume of this air in the diver's lungs at depth, assuming temperature remains constant?

Accepted Answer

$$0.67\ \mathrm{L}$$

Question 2

Which of the following best explains why gases are compressible?

Accepted Answer

Gas molecules occupy a small fraction of the total volume, leaving mostly empty space.

Question 3

A weather balloon is filled with helium to a volume of $$500.0\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$20.0^\circ\mathrm{C}. If $$the balloon rises to an altitude where the pressure is $$0.500\ \mathrm{atm}$$ and the temperature is $$-10.0^\circ\mathrm{C}$$, what is the new volume of the balloon? (Assume ideal gas behavior.)

Accepted Answer

$$820\ \mathrm{L}$$

Question 4

Which of the following statements about the kinetic-molecular theory of gases is correct?

Accepted Answer

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

Question 5

A mixture contains $$2.0\ \mathrm{mol} of$$ $$\mathrm{N}_2$$ and $$3.0\ \mathrm{mol} of$$ $$\mathrm{O}_2 in a$$ $$10.0\ \mathrm{L}$$ container at $$27^\circ\mathrm{C}. $$What is the partial pressure of $$\mathrm{O}_2 in $$the mixture? $$(R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$6.07\ \mathrm{atm}$$

Question 6

Which of the following correctly expresses the relationship described by Avogadro's Law?

Accepted Answer

$$V \propto n (at $$constant $$T$$ and $$P)$$

Question 7

A $$5.00\ \mathrm{g}$$ sample of an unknown gas occupies $$2.00\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$273\ \mathrm{K}. $$What is the molar mass of the gas?

Accepted Answer

$$56.0\ \mathrm{g\ $$mol^{-1}$$}$$

Question 8

Which of the following is NOT a characteristic property of gases?

Accepted Answer

They have a definite shape and volume.

Question 9

A $$1.00\ \mathrm{L}$$ flask contains $$0.50\ \mathrm{mol} of$$ $$\mathrm{H}_2$$ and $$0.50\ \mathrm{mol} of$$ $$\mathrm{N}_2 at$$ $$0^\circ\mathrm{C}. $$What is the total pressure in the flask? $$(R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$9.12\ \mathrm{atm}$$

Question 10

Which of the following best describes Dalton's Law of Partial Pressures?

Accepted Answer

The total pressure of a gas mixture is the sum of the partial pressures of each component gas.

Question 11

A $$10.0\ \mathrm{g}$$ sample of $$\mathrm{CO}_2 is $$placed in a $$5.00\ \mathrm{L}$$ container at $$25^\circ\mathrm{C}. $$What is the pressure in the container? $$(R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$0.90\ \mathrm{atm}$$

Question 12

Which of the following statements about diffusion and effusion is correct?

Accepted Answer

Effusion occurs faster for lighter gas molecules than for heavier ones.

Question 13

At STP, what is the molar volume of an ideal gas?

Accepted Answer

$$22.4\ \mathrm{L}$$

Question 14

A $$2.00\ \mathrm{L}$$ container holds a mixture of $$1.00\ \mathrm{mol} of$$ $$\mathrm{He}$$ and $$2.00\ \mathrm{mol} of$$ $$\mathrm{Ne} at$$ $$27^\circ\mathrm{C}. $$What is the mole fraction of $$\mathrm{He} in $$the mixture?

Accepted Answer

$$0.33$$

Question 15

Which of the following equations correctly relates the density of a gas to its molar mass, pressure, and temperature?

Accepted Answer

$$d = \dfrac{P M}{R T}$$

Question 16

A sample of gas at $$300\ \mathrm{K}$$ has an average kinetic energy of $$KE. If $$the temperature is increased to $$600\ \mathrm{K}$$, what happens to the average kinetic energy?

Accepted Answer

It doubles.

Question 17

Which of the following is a correct statement about the behavior of real gases compared to ideal gases?

Accepted Answer

Real gases behave ideally at low pressure and high temperature.

Question 18

A $$3.00\ \mathrm{L}$$ container holds $$0.50\ \mathrm{mol} of$$ $$\mathrm{O}_2 at$$ $$27^\circ\mathrm{C}. $$What is the pressure inside the container? $$(R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$4.10\ \mathrm{atm}$$

Question 19

Which of the following best explains why helium balloons deflate faster than air-filled balloons?

Accepted Answer

Helium atoms are lighter and effuse through the balloon material faster than air molecules.

Chapter 6: Gases – Properties, Laws, and Theories

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