CHEM 121 Module 6 Exam: Gas Laws and Thermochemistry
2026/2027 UPDATE
1. Which of the following is an assumption of the Kinetic Molecular Theory of
gases?
A. Gas particles move in fixed, circular orbits.
B. Collisions between gas particles result in a loss of total kinetic energy.
C. Intermolecular forces between gas particles are very strong.
D. The volume of individual gas particles is negligible compared to the total volume.
Answer: D
Rationale: Kinetic Molecular Theory assumes that gas particles are so small compared to
the distances between them that their individual volume is assumed to be zero.
2. According to Boyle’s Law, if the volume of a gas is halved at constant
temperature, what happens to the pressure?
A. The pressure is halved.
B. The pressure remains the same.
C. The pressure quadruples.
D. The pressure doubles.
Answer: D
Rationale: Boyle’s Law states that pressure and volume are inversely proportional (P1V1 =
P2V2). Halving the volume results in doubling the pressure.
,3. A sample of gas has a volume of 2.0 L at 273 K. What will be its volume at 546
K if pressure is held constant?
A. 1.0 L
B. 2.0 L
C. 8.0 L
D. 4.0 L
Answer: D
Rationale: According to Charles’s Law (V1/T1 = V2/T2), volume is directly proportional to
absolute temperature. Doubling the temperature from 273 K to 546 K doubles the volume
from 2.0 L to 4.0 L.
4. Which state of matter is the most compressible?
A. Solid
B. Gas
C. Liquid
D. Plasma
Answer: B
Rationale: Gases are highly compressible because there is a large amount of empty space
between the particles.
5. What is the standard molar volume of an ideal gas at STP?
A. 1.0 L
B. 22.4 L
C. 24.5 L
D. 273 L
Answer: B
Rationale: At Standard Temperature and Pressure (STP), one mole of any ideal gas
occupies a volume of 22.4 liters.
, 6. A reaction that releases heat into the surroundings is classified as:
A. Endothermic
B. Adiabatic
C. Isothermic
D. Exothermic
Answer: D
Rationale: Exothermic reactions release energy, usually in the form of heat, to the
surroundings.
7. Calculate the amount of heat (q) required to raise the temperature of 50.0 g
of water from 20.0 C to 30.0 C. (Specific heat of water = 4.184 J/g C)
A. 2092 J
B. 418.4 J
C. 209.2 J
D. 4184 J
Answer: A
Rationale: Using q = mcΔT: q = (50.0 g)(4.184 J/g C)(10.0 C) = 2092 J.
8. Which of the following variables is NOT part of the Ideal Gas Law equation?
A. Pressure (P)
B. Volume (V)
C. Velocity (v)
D. Temperature (T)
Answer: C
Rationale: The Ideal Gas Law is PV = nRT. Velocity is not a variable in this macroscopic
equation.
2026/2027 UPDATE
1. Which of the following is an assumption of the Kinetic Molecular Theory of
gases?
A. Gas particles move in fixed, circular orbits.
B. Collisions between gas particles result in a loss of total kinetic energy.
C. Intermolecular forces between gas particles are very strong.
D. The volume of individual gas particles is negligible compared to the total volume.
Answer: D
Rationale: Kinetic Molecular Theory assumes that gas particles are so small compared to
the distances between them that their individual volume is assumed to be zero.
2. According to Boyle’s Law, if the volume of a gas is halved at constant
temperature, what happens to the pressure?
A. The pressure is halved.
B. The pressure remains the same.
C. The pressure quadruples.
D. The pressure doubles.
Answer: D
Rationale: Boyle’s Law states that pressure and volume are inversely proportional (P1V1 =
P2V2). Halving the volume results in doubling the pressure.
,3. A sample of gas has a volume of 2.0 L at 273 K. What will be its volume at 546
K if pressure is held constant?
A. 1.0 L
B. 2.0 L
C. 8.0 L
D. 4.0 L
Answer: D
Rationale: According to Charles’s Law (V1/T1 = V2/T2), volume is directly proportional to
absolute temperature. Doubling the temperature from 273 K to 546 K doubles the volume
from 2.0 L to 4.0 L.
4. Which state of matter is the most compressible?
A. Solid
B. Gas
C. Liquid
D. Plasma
Answer: B
Rationale: Gases are highly compressible because there is a large amount of empty space
between the particles.
5. What is the standard molar volume of an ideal gas at STP?
A. 1.0 L
B. 22.4 L
C. 24.5 L
D. 273 L
Answer: B
Rationale: At Standard Temperature and Pressure (STP), one mole of any ideal gas
occupies a volume of 22.4 liters.
, 6. A reaction that releases heat into the surroundings is classified as:
A. Endothermic
B. Adiabatic
C. Isothermic
D. Exothermic
Answer: D
Rationale: Exothermic reactions release energy, usually in the form of heat, to the
surroundings.
7. Calculate the amount of heat (q) required to raise the temperature of 50.0 g
of water from 20.0 C to 30.0 C. (Specific heat of water = 4.184 J/g C)
A. 2092 J
B. 418.4 J
C. 209.2 J
D. 4184 J
Answer: A
Rationale: Using q = mcΔT: q = (50.0 g)(4.184 J/g C)(10.0 C) = 2092 J.
8. Which of the following variables is NOT part of the Ideal Gas Law equation?
A. Pressure (P)
B. Volume (V)
C. Velocity (v)
D. Temperature (T)
Answer: C
Rationale: The Ideal Gas Law is PV = nRT. Velocity is not a variable in this macroscopic
equation.
