**Examples of Multiple Choice Gas Kinetic Theory Questions and Answer Keys – Kinetic Theory** (or kinetic theory of gases) attempts to explain macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion.

In essence, this theory states that pressure is not caused by static pulses between molecules, as Isaac Newton suspected, but is caused by collisions between molecules moving at different speeds.

Kinetic Theory is also known as Kinetic-Molecular Theory or Collision Theory or Kinetic Theory on Gases.

## 1 – 10 Examples of Kinetic Theory of Gases and Answers

1. An ideal gas is in a closed space with a volume V, pressure P and temperature T. If the volume changes to 1/2 times the original and the temperature is increased to 4 times the original, then the pressure of the gas in the system becomes….

A. 8 P1

B. 2 P1

C. 1/2 P1

D. 1/4 P1

E. 1/8 P1

**Discussion:**

**Answer: A**

2. An ideal gas initially occupies a space whose volume is V at temperature T and pressure P. If the temperature of the gas becomes 3/2 T and the pressure becomes 2 P, then the volume of the gas becomes ….

A. 3/4 V

B. 4/3 V

C. 3/2 V

D. 3 V

E. 4 V

**Discussion:**

**Answer: A**

3. A total of 3 liters of Argon gas at 27°C at a pressure of 1 atm (1 atm = 105 Pa) is in the tube. If the general gas constant R = 8.314 J mol−1 K−1 and the number of particles in 1 mole of gas is 6.02 x 1023 particles, then the number of Argon gas particles in the cylinder is…

A. 0.83 x 10²³ particles

B. 0.72 x 10²³ particles

C. 0.42 x 10²³ particles

D. 0.22 x 10²³ particles

E. 0.12 x 10²³ particles

**Discussion:**

**Answer: B**

4. Gas pressure in an enclosed space:

- 1) Comparable to the average velocity of the gas particles.
- 2) Comparable to the average kinetic energy of the gas particles.
- 3) Inversely proportional to the volume of gas.
- 4) Does not depend on the number of gas particles.

The correct statement is…

A. 1, 2, and 3

B. 1, 2, 3, and 4

C. 1 and 3

D. 2 and 4

E. 4 only

**Discussion:**

See the gas pressure equation.

**Answer: A**

5. Two moles of gas occupy 24.08 L of space. Each gas molecule has a kinetic energy of 3 . 10–21 Joules. If Avogadro’s number is 6.02 . 1023 particles then the gas pressure in the tank is…

A. 1.00 . 10² Pa

B. 2.41 . 10² Pa

C. 6.02 . 10² Pa

D. 1.00 . 10^5 Pa

E. 2.41 . 10^5 Pa

**Discussion:**

**Answer : D**

### See also: Problem Harmonic Vibration (Simple Harmonic Motion)

6. An ideal gas with pressure P and volume V. If the pressure of the gas in the space becomes times the original at a constant volume, then the ratio of kinetic energy before and after the pressure drop is…

A. 1: 4

B. 1: 2

C. 2 : 1

D. 4 : 1

E. 5 : 1

**Discussion:**

**Answer : D**

7. An enclosed space contains an ideal gas with a temperature T and the velocity of the gas particles in it v. If the temperature of the gas is increased by 2T, the velocity of the gas particles will be…

A. 2 v

B. v

C. 2 v

D. 4 v

E.v2

**Discussion:**

**Answer: A**

8. In an enclosed space there is a gas with a temperature of 27oC. If a gas is heated until its kinetic energy is 5 times its original value, then the gas must be heated to a temperature…

A. 100**°**C

B. 135**°**C

C. 1200**°**C

D. 1227**°**C

E. 1500**°**C

**Discussion:**

**Answer : D**

9. An ideal amount of gas in a closed tube is heated isochoric so that its temperature rises 4 times. The average kinetic energy of an ideal gas molecule is…

A. times again

B. times again

C. Same as before

D. 2 times again

E. 4 times again

**Discussion:**

From the equation of gas kinetic energy Ek = 3/2 k T, it shows that the kinetic energy is proportional to the temperature. This means that if the temperature rises 4 times the original means that the kinetic energy increases 4 times the original.

**Answer: E**

10. The ideal gas temperature in the cylinder is defined as absolute and Ek represents the average kinetic energy of the gas molecules. Based on these equations…

A. The higher the temperature, the lower the kinetic energy.

B. The higher the temperature, the slower the particles move.

C. The higher the temperature, the faster the particles move.

D. The temperature of the gas is inversely proportional to the kinetic energy.

E. The temperature of the gas does not affect the motion of the particles.

**Discussion:**

From the equation of gas kinetic energy Ek = 3/2 k T, it shows that the kinetic energy is proportional to the temperature. So the higher the temperature, the greater the kinetic energy. The greater the kinetic energy, the faster the particles move.

**Answer: C**