Lesson 9.2.2

9.2.2 Kinetic theory and the ideal gas equation Quiz: Pearson Edexcel Physics, Unit 9

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 9.2.2, Kinetic theory and the ideal gas equation: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 9: Thermodynamics, written with Revision Ninja.

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The 20 questions

  1. Gas pressure on a container wall results from molecules undergoing a rate of change of what?

    • Potential energy
    • Charge
    • Momentum
    • Mass

  2. In pV = NkT, what is the unit of k?

    • J K^-1
    • W K^-1
    • J mol^-1
    • J kg^-1 K^-1

  3. How is the molar gas constant R related to the Boltzmann constant k?

    • R = N_A / k
    • R = k / N_A
    • R = N_A k
    • k = N_A R

  4. What is assumed about the forces between molecules in an ideal gas?

    • Zero outside collisions
    • Always attractive
    • Always repulsive
    • Proportional to distance

  5. Which graph line shows an isothermal change when pressure p is plotted against 1/V?

    • Hyperbolic curve
    • Vertical straight line
    • Horizontal straight line
    • Straight through origin

  6. Absolute temperature is directly proportional to which property of ideal gas molecules?

    • Mean speed
    • Mean free path
    • Mean kinetic energy
    • Total momentum

  7. A gas of 3.0 x 10^23 molecules at 300 K occupies 0.020 m^3. What is its pressure? Use k = 1.38 x 10^-23 J K^-1.

    • 6.2 x 10^4 Pa
    • 1.2 x 10^6 Pa
    • 6.2 x 10^2 Pa
    • 3.1 x 10^4 Pa

  8. At 1.0 x 10^5 Pa and 300 K, a gas occupies 0.0249 m^3. How many moles are present? Use R = 8.31 J mol^-1 K^-1.

    • 0.10 mol
    • 10 mol
    • 1.0 mol
    • 2.5 mol

  9. A fixed mass of ideal gas is compressed isothermally to half its volume. What happens to its pressure?

    • It stays constant
    • It halves
    • It quadruples
    • It doubles

  10. A gas of density 1.2 kg m^-3 has pressure 1.0 x 10^5 Pa. What is its root-mean-square speed?

    • 250 m s^-1
    • 2.0 x 10^2 m s^-1
    • 500 m s^-1
    • 1.2 x 10^3 m s^-1

  11. What is the mean translational kinetic energy per molecule of an ideal gas at 400 K?

    • 2.1 x 10^-21 J
    • 1.4 x 10^-23 J
    • 5.5 x 10^-21 J
    • 8.3 x 10^-21 J

  12. A fixed volume of gas has its absolute temperature raised from 300 K to 450 K. What is the ratio of final to initial pressure?

    • 1.0
    • 1.5
    • 2.0
    • 0.67

  13. How many molecules are in 0.50 mol of gas? Use N_A = 6.02 x 10^23 mol^-1.

    • 1.2 x 10^24
    • 6.0 x 10^22
    • 3.0 x 10^23
    • 6.0 x 10^23

  14. A gas at 2.0 x 10^5 Pa and 300 K is heated at constant volume to 450 K. What is its pressure?

    • 2.0 x 10^5 Pa
    • 4.5 x 10^5 Pa
    • 3.0 x 10^5 Pa
    • 1.3 x 10^5 Pa

  15. If the number of molecules and the volume are both doubled while the temperature is held constant, what happens to the pressure?

    • It halves.
    • It doubles.
    • It quadruples.
    • It is unchanged.

  16. The number of molecules in an ideal gas doubles at constant volume and temperature. What happens to pressure?

    • It stays constant
    • It doubles
    • It quadruples
    • It halves

  17. Which molecular property directly links absolute temperature to the kinetic energy of an ideal gas?

    • Mean square speed
    • Mean speed
    • Root mean speed
    • Most probable speed

  18. Which quantity is NOT directly present in the ideal gas equation pV = NkT?

    • Gas volume
    • Absolute temperature
    • Number of molecules
    • Molecular mass

  19. Under which conditions do real gases deviate most from ideal gas behaviour?

    • High pressure, low temperature
    • High pressure, high temperature
    • Low pressure, high temperature
    • Low pressure, low temperature

  20. A gas contains N molecules, each with mean square speed <c^2>, in a volume V at pressure p. Which expression is correct?

    • p = N m <c^2> / (3V)
    • p = N m <c^2> / (2V)
    • p = 3 N m <c^2> / V
    • p = N m <c> / (3V)

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