Lesson 5.6.2.2

5.6.2.2 Energy changes and reversible reactions Quiz: AQA Combined Science, Unit 13

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.6.2.2, Energy changes and reversible reactions: 20 multiple choice questions for the AQA GCSE Combined Science (8464), Unit 13: The rate and extent of chemical change, written with Revision Ninja.

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The 20 questions

  1. If a reversible reaction is exothermic in one direction, it is ___ in the opposite direction.

    • Endothermic
    • Neutral
    • Exothermic
    • Catalysed

  2. How do the amounts of energy transferred in the forward and reverse directions of a reversible reaction compare?

    • Always decreasing
    • Always increasing
    • Completely different
    • Exactly the same

  3. If the forward reaction absorbs 65 kJ/mol, what is the energy change for the reverse reaction?

    • 0 kJ/mol
    • -65 kJ/mol
    • +65 kJ/mol
    • +130 kJ/mol

  4. The forward reaction has an energy change of -120 kJ/mol. Which describes the reverse reaction?

    • -120 kJ/mol, exothermic
    • +240 kJ/mol, endothermic
    • +120 kJ/mol, endothermic
    • 0 kJ/mol, neutral

  5. Why is the energy transfer equal and opposite for the two directions of a reversible reaction?

    • Same bonds reverse
    • Temperature changes
    • Energy is destroyed
    • Different atoms form

  6. Which quantity remains identical in magnitude for both directions of a reversible reaction?

    • Reaction rate
    • Energy transferred
    • Activation energy
    • Equilibrium yield

  7. A forward reaction releases 92 kJ. What does the reverse reaction do?

    • Releases 46 kJ
    • Absorbs 184 kJ
    • Absorbs 92 kJ
    • Releases 92 kJ

  8. A forward reaction absorbs energy. In the reverse direction the temperature of the surroundings:

    • Rises
    • Stays exactly constant
    • Becomes zero
    • Falls

  9. A forward reaction warms its surroundings. What does the reverse reaction do to the surroundings?

    • Warms them
    • Has no effect
    • Cools them
    • Boils them

  10. Heating hydrated copper(II) sulfate removes water, which is endothermic. Adding water back is:

    • Catalysed
    • Exothermic
    • Endothermic
    • Neutral

  11. Which energy rule applies to the forward and reverse directions of a reversible reaction?

    • Energy is created
    • Energy is conserved
    • Energy doubles
    • Energy is lost

  12. In an energy profile, the reverse reaction compared with the forward reaction has its reactant and product levels:

    • Reversed in colour
    • The same
    • Both at zero
    • Swapped

  13. Which direction of an endothermic reaction absorbs energy from the surroundings?

    • The forward direction
    • Both directions
    • Neither direction
    • The reverse direction

  14. A reaction absorbs 150 kJ going forward. For the same amount, the reverse reaction:

    • Releases nothing
    • Releases 150 kJ
    • Releases 300 kJ
    • Absorbs 75 kJ

  15. One mole of a product releases 50 kJ when formed. How much energy is absorbed when one mole breaks back down?

    • 25 kJ
    • 100 kJ
    • 50 kJ
    • 0 kJ

  16. A forward reaction transfers 30 kJ per mole. For 2 mol, the energy transferred is:

    • 90 kJ
    • 15 kJ
    • 30 kJ
    • 60 kJ

  17. For N2O4 to 2NO2, if the forward reaction is endothermic, the reverse 2NO2 to N2O4 is:

    • Catalysed
    • Neutral
    • Endothermic
    • Exothermic

  18. An endothermic forward reaction cools its surroundings. What does the reverse reaction do?

    • Cool surroundings
    • No temperature change
    • Freeze surroundings
    • Warm surroundings

  19. In an energy profile for a reversible reaction, how do the energy gaps between reactants and products compare?

    • Same size
    • Always larger
    • Always smaller
    • Zero difference

  20. A reaction is endothermic in the forward direction. Which way does energy flow in the reverse direction?

    • To surroundings
    • Nowhere at all
    • From surroundings
    • Into the system

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