Lesson 9.2.1

9.2.1 Internal energy and absolute zero Quiz: Pearson Edexcel Physics, Unit 9

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 9.2.1, Internal energy and absolute zero: 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. Internal energy is the sum of which two molecular energies?

    • Thermal and mechanical
    • Potential and chemical
    • Kinetic and nuclear
    • Kinetic and potential

  2. What is the lowest possible temperature on the kelvin scale?

    • 273 K
    • 0 C
    • -100 K
    • 0 K

  3. What is the theoretical mean kinetic energy of molecules at absolute zero?

    • Negative
    • 1 J
    • 0 J
    • Infinite

  4. The mean translational kinetic energy per molecule of an ideal gas is

    • (3/2) k T^2
    • (2/3) k T
    • (3/2) k T
    • (1/2) k T

  5. The Boltzmann constant k has the approximate value

    • 1.38 x 10^-23 J K^-1
    • 6.02 x 10^23 mol^-1
    • 8.31 J mol^-1 K^-1
    • 6.63 x 10^-34 J s

  6. A gas has mean molecular kinetic energy 6.21 x 10^-21 J. Using k = 1.38 x 10^-23 J K^-1, what is its absolute temperature?

    • 600 K
    • 450 K
    • 300 K
    • 200 K

  7. A gas is cooled from 127 C to -73 C. What is the ratio of its initial to its final absolute temperature?

    • 2.0
    • 0.5
    • 1.5
    • 4.0

  8. Compared to 300 K, what is the mean kinetic energy of gas molecules at 600 K?

    • Equal
    • Half
    • Double
    • Quadruple

  9. Convert 25 C to absolute temperature.

    • 25 K
    • 273 K
    • 248 K
    • 298 K

  10. Two different ideal gases are at the same temperature. How do their mean translational kinetic energies compare?

    • Higher for lighter
    • Higher for heavier
    • Zero for both
    • Identical

  11. Why does water at 0 °C still possess internal energy?

    • No particle motion
    • At absolute zero
    • Above absolute zero
    • Zero kinetic energy

  12. Gas A has double the molecules of Gas B at the same temperature. What is Gas A's internal energy?

    • Twice Gas B
    • Half Gas B
    • Equal Gas B
    • Fourfold Gas B

  13. 2.0 mol of an ideal monatomic gas is at 300 K, where the mean kinetic energy per molecule is 6.21 x 10^-21 J. What is the total translational kinetic energy? Use N_A = 6.02 x 10^23 mol^-1.

    • 7.5 kJ
    • 3.7 kJ
    • 15 kJ
    • 0.37 kJ

  14. Absolute temperature of a gas is directly proportional to which particle property?

    • Particle mass
    • Mean particle velocity
    • Total potential energy
    • Mean kinetic energy

  15. Which molecular energy is assumed to be zero in an ideal gas?

    • Kinetic energy
    • Potential energy
    • Total energy
    • Thermal energy

  16. The mean kinetic energy per molecule of an ideal gas rises from 4.14 x 10^-21 J to 8.28 x 10^-21 J. Between which temperatures does the gas change?

    • from 300 K to 400 K
    • from 200 K to 400 K
    • from 100 K to 200 K
    • from 200 K to 800 K

  17. Which change reduces the internal energy of a fixed sample of ideal gas?

    • Increasing pressure
    • Increasing volume
    • Raising temperature
    • Lowering temperature

  18. A gas contains 1 mol of a monatomic ideal gas at 300 K. Using the given result that its internal energy is (3/2)RT per mole, with R = 8.31 J mol^-1 K^-1, what is the internal energy?

    • 7.5 kJ
    • 0.37 kJ
    • 2.5 kJ
    • 3.7 kJ

  19. Unlike temperature, total internal energy of an ideal gas sample depends directly on what?

    • Container shape
    • Number of particles
    • Particle speed
    • Boltzmann constant

  20. The mean kinetic energy per molecule of a gas at 273 K is 5.65 x 10^-21 J. At what temperature is it 1.13 x 10^-20 J?

    • 819 K
    • 546 K
    • 1092 K
    • 273 K

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