Q: Which equation correctly expresses the relationship between pressure, force, and area?

$\text{pressure} = \dfrac{\text{force}}{\text{area}}$

Q: A sample of gas has a volume of 2.80 L at an unknown temperature. When cooled to 0°C (273 K), its volume decreases to 2.57 L. What was the initial temperature in kelvin?

$T_1 = \dfrac{2.80 \times 273}{2.57} = 297$ K

Q: A 4.8-L sample of helium contains 0.22 mol. How many additional moles are needed to increase the volume to 6.4 L at constant temperature and pressure?

$n_2 = \dfrac{6.4}{4.8} \times 0.22 = 0.29$ mol; \text{add } 0.07$ mol

Q: A sample of gas has a mass of 0.136 g, a volume of 0.112 L, a temperature of 298 K, and a pressure of 1.06 atm. What is its molar mass?

$\text{Molar mass} = \dfrac{0.136}{0.00485} = 28.0$ g/mol

Question 1

Which statement best explains why a straw cannot be longer than about 10.3 meters, even with a perfect vacuum at the top?

Accepted Answer

Atmospheric pressure can only support a column of liquid up to the height where its weight equals atmospheric pressure.

Question 2

According to the kinetic molecular theory, which of the following is NOT a property of an ideal gas?

Accepted Answer

Gas particles attract and repel each other.

Question 3

A scuba diver at a depth of 20 m breathes air at a pressure of 3 atm. If the diver ascends rapidly to the surface (1 atm) while holding his breath, what happens to the volume of air in his lungs according to Boyle's Law?

Accepted Answer

The volume increases by a factor of 3.

Question 4

Which equation correctly expresses the relationship between pressure, force, and area?

Accepted Answer

$	ext{pressure} = \dfrac{	ext{force}}{	ext{area}}$

Question 5

Convert a pressure of 0.311 atm to millimeters of mercury (mm Hg).

Accepted Answer

$0.311 	imes 760 = 236$ mm Hg

Question 6

Which of the following best describes why gases are compressible while liquids are not?

Accepted Answer

There is much more empty space between gas particles than between liquid particles.

Question 7

A sample of gas has a volume of 2.80 L at an unknown temperature. When cooled to 0°C (273 K), its volume decreases to 2.57 L. What was the initial temperature in kelvin?

Accepted Answer

$T_1 = \dfrac{2.80 	imes 273}{2.57} = 297$ K

Question 8

Which of the following is the correct form of Boyle's Law for two sets of conditions?

Accepted Answer

$P_1 V_1 = P_2 V_2$

Question 9

A mixture of gases contains 78% nitrogen, 21% oxygen, and 1% argon at a total pressure of 1 atm. What is the partial pressure of oxygen?

Accepted Answer

$0.21 	imes 1 = 0.21$ atm

Question 10

Which of the following statements about the ideal gas law is correct?

Accepted Answer

The ideal gas law combines pressure, volume, temperature, and number of moles in the equation $PV = nRT$.

Question 11

A 4.8-L sample of helium contains 0.22 mol. How many additional moles are needed to increase the volume to 6.4 L at constant temperature and pressure?

Accepted Answer

$n_2 = \dfrac{6.4}{4.8} 	imes 0.22 = 0.29$ mol; 	ext{add } 0.07$ mol

Question 12

A sample of gas has a mass of 0.136 g, a volume of 0.112 L, a temperature of 298 K, and a pressure of 1.06 atm. What is its molar mass?

Accepted Answer

$	ext{Molar mass} = \dfrac{0.136}{0.00485} = 28.0$ g/mol

Question 13

Which of the following is a real-world consequence of low atmospheric pressure at high altitudes?

Accepted Answer

Decreased partial pressure of oxygen can cause hypoxia, leading to dizziness and shortness of breath.

Question 14

A balloon filled with air at constant pressure is heated. According to Charles's Law, what happens to the volume of the balloon?

Accepted Answer

The volume increases.

Question 15

Which of the following is the correct combined gas law equation?

Accepted Answer

$\dfrac{P_1 V_1}{T_1} = \dfrac{P_2 V_2}{T_2}$

Question 16

A mixture of helium, neon, and argon has a total pressure of 558 mm Hg. If the partial pressures of helium and neon are 341 mm Hg and 112 mm Hg, respectively, what is the partial pressure of argon?

Accepted Answer

$P_{Ar} = 558 - 341 - 112 = 105$ mm Hg

Question 17

Which of the following pollutants is primarily emitted by motor vehicles and can displace oxygen in the blood?

Accepted Answer

Carbon monoxide ($CO$)

Question 18

At standard temperature and pressure (STP), what volume does 1 mole of an ideal gas occupy?

Accepted Answer

$22.4$ L

Question 19

A diver breathes a heliox mixture containing 2.0% oxygen at a depth of 90 m, where the total pressure is 10.0 atm. What is the partial pressure of oxygen?

Accepted Answer

$0.02 	imes 10.0 = 0.20$ atm

Study Notes: Chapter 11 – Gases (Introductory Chemistry)

Study Guide - Practice Questions

Study Guide - Flashcards