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AP Chemistry Practice Quiz: Ideal Gas Law

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 10 questions to check your progress.

Question 1 of 10

According to the ideal gas law, what is the relationship between the pressure and absolute temperature of a fixed amount of gas in a rigid container?

All Questions (10)

According to the ideal gas law, what is the relationship between the pressure and absolute temperature of a fixed amount of gas in a rigid container?

A) They are inversely proportional.

B) They are directly proportional.

C) There is no relationship between them.

D) The pressure is proportional to the square of the temperature.

Correct Answer: B

The ideal gas law is PV=nRT. For a fixed amount of gas (n is constant) in a rigid container (V is constant), the equation simplifies to P = (nR/V)T. This shows that pressure (P) is directly proportional to the absolute temperature (T).

A sealed, flexible container holds a sample of an ideal gas at a constant pressure. If the absolute temperature of the gas is doubled, what happens to the volume of the container?

A) The volume is halved.

B) The volume is doubled.

C) The volume remains the same.

D) The volume is quadrupled.

Correct Answer: B

From the ideal gas law, PV=nRT, if pressure (P) and the amount of gas (n) are held constant, volume (V) is directly proportional to absolute temperature (T). Therefore, doubling the temperature will cause the volume to double.

A gas mixture in a container has a total pressure of 3.0 atm. The mixture consists of Gas X and Gas Y. If the partial pressure of Gas X is 1.2 atm, what is the partial pressure of Gas Y?

A) 0.4 atm

B) 1.8 atm

C) 3.0 atm

D) 4.2 atm

Correct Answer: B

The total pressure of a gas mixture is the sum of the partial pressures of its components (P_total = PX + PY). Therefore, the partial pressure of Gas Y is P_total - PX = 3.0 atm - 1.2 atm = 1.8 atm.

A container holds a mixture of 1 mole of helium (He) and 4 moles of neon (Ne). If the total pressure is 10 atm, what is the partial pressure of helium?

A) 1 atm

B) 2 atm

C) 8 atm

D) 10 atm

Correct Answer: B

The partial pressure of a component is its mole fraction multiplied by the total pressure (PA = P_total * XA). The total moles are 1 + 4 = 5 moles. The mole fraction of helium is 1/5 = 0.2. Therefore, the partial pressure of helium is 10 atm * 0.2 = 2 atm.

A graph is created to represent the behavior of a fixed amount of an ideal gas at constant temperature. If pressure (P) is plotted on the y-axis and volume (V) is plotted on the x-axis, what will the shape of the curve be?

A) A straight line with a positive slope passing through the origin.

B) A horizontal line.

C) A hyperbola.

D) A straight line with a negative slope.

Correct Answer: C

The ideal gas law is PV=nRT. At constant temperature (T) and amount of gas (n), the product PV is a constant (PV=k). This describes an inverse relationship between P and V, which is graphically represented by a hyperbola.

In an ideal gas mixture, the partial pressure of each component gas is independent of the others and is proportional to what property of that component in the mixture?

A) Its molar mass

B) Its molecular volume

C) Its mole fraction

D) Its chemical reactivity

Correct Answer: C

The provided content states that in an ideal gas mixture, each component's partial pressure is proportional to its mole fraction (PA = P_total * XA).

A rigid 2.0 L container holds 0.5 mol of Gas A and 1.5 mol of Gas B. If the partial pressure of Gas A is 3.0 atm, what is the total pressure in the container?

A) 4.0 atm

B) 6.0 atm

C) 9.0 atm

D) 12.0 atm

Correct Answer: D

The partial pressure is proportional to the mole fraction. The mole fraction of Gas A is 0.5 / (0.5 + 1.5) = 0.5 / 2.0 = 0.25. We know PA = P_total * XA. Rearranging gives P_total = PA / XA. So, P_total = 3.0 atm / 0.25 = 12.0 atm.

Which graph correctly represents the relationship between the volume (V) and the number of moles (n) of an ideal gas, assuming constant temperature and pressure?

A) A horizontal line, indicating V is independent of n.

B) A hyperbolic curve, indicating V is inversely proportional to n.

C) A straight line passing through the origin, indicating V is directly proportional to n.

D) A parabolic curve.

Correct Answer: C

From the ideal gas law, PV=nRT, if T and P are held constant, the equation can be arranged to V = n(RT/P). Since RT/P is a constant, this shows a direct linear relationship between V and n (V = kn), which is represented by a straight line passing through the origin.

The equation PV=nRT is known as the:

A) Law of Partial Pressures

B) Ideal Gas Law

C) Law of Mole Fractions

D) Avogadro's Law

Correct Answer: B

The content explicitly identifies the equation PV=nRT as the ideal gas law, which relates the macroscopic properties of ideal gases.

A container holds a mixture of gases with a total pressure P_total. The mixture contains 25% moles of Gas A, 35% moles of Gas B, and 40% moles of Gas C. If Gas B is completely removed from the container at constant volume and temperature, what is the new total pressure?

A) 0.35 * P_total

B) 0.40 * P_total

C) 0.65 * P_total

D) 0.75 * P_total

Correct Answer: C

The initial partial pressures are PA = 0.25*P_total, PB = 0.35*P_total, and PC = 0.40*P_total. When Gas B is removed, only Gas A and Gas C remain. The new total pressure will be the sum of their original partial pressures: P_new = PA + PC = (0.25 * P_total) + (0.40 * P_total) = 0.65 * P_total.