Lesson 13B.1

13B.1 Entropy and the total entropy change Quiz: Pearson Edexcel Chemistry, Unit 13

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 13B.1, Entropy and the total entropy change: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 13: Energetics II, written with Revision Ninja.

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The 20 questions

  1. In chemical thermodynamics, what fundamental property does entropy measure?

    • Total enthalpy change
    • Rate of reaction
    • Dispersal of energy
    • Activation energy

  2. For a spontaneous process to occur, what must happen to the total entropy change?

    • Must be zero
    • Must be constant
    • Must be negative
    • Must be positive

  3. Which process results in an increase in the entropy of a system?

    • A gas condensing
    • A gas dissolving
    • A solid melting
    • A liquid freezing

  4. Why does the reaction N2O4(g) -> 2NO2(g) have a positive system entropy change?

    • Gas moles decrease
    • Enthalpy is negative
    • Gas moles increase
    • Temperature drops

  5. What causes an increase in system entropy when an ionic lattice dissolves in water?

    • Water evaporates
    • Temperature decreases
    • Ions form lattice
    • Ions disperse

  6. Which expression gives the total entropy change of a reaction?

    • dStotal = dSsystem - dSsurroundings
    • dStotal = dSsystem + dSsurroundings
    • dStotal = dHsystem + dSsurroundings
    • dStotal = dSsystem x dSsurroundings

  7. What are the units of entropy?

    • K mol J-1
    • J K-1 mol-1
    • kJ mol-1
    • J mol-1

  8. Calculate dSsystem for CaCO3(s) gives CaO(s) + CO2(g), using standard entropies of CaCO3 = 93, CaO = 40 and CO2 = 214 J K-1 mol-1. What is the entropy change of the system?

    • +347 J K-1 mol-1
    • +161 J K-1 mol-1
    • -161 J K-1 mol-1
    • -347 J K-1 mol-1

  9. What is the entropy change of the surroundings for a reaction with dH = -92 kJ mol-1 at 298 K?

    • +0.309 J K-1 mol-1
    • +309 J K-1 mol-1
    • +92 J K-1 mol-1
    • -309 J K-1 mol-1

  10. A reaction has dSsystem = -150 J K-1 mol-1 and dH = -92 kJ mol-1 at 298 K. What is dStotal?

    • -241 J K-1 mol-1
    • +459 J K-1 mol-1
    • -159 J K-1 mol-1
    • +159 J K-1 mol-1

  11. What happens to the surroundings during an exothermic reaction to give a positive entropy change?

    • Heat is absorbed
    • Gas is absorbed
    • Heat is transferred
    • Volume decreases

  12. What allows the endothermic dissolution of ammonium nitrate to occur spontaneously at room temperature?

    • Negative entropy change
    • Exothermic enthalpy change
    • High activation energy
    • Positive entropy change

  13. What is the sign of the system entropy change for the reaction 2Mg(s) + O2(g) -> 2MgO(s)?

    • Negative
    • Variable
    • Positive
    • Zero

  14. Which phase change results in the largest positive system entropy change per mole?

    • Liquid to gas
    • Gas to liquid
    • Solid to liquid
    • Liquid to solid

  15. Why does the reaction between ethanoic acid and ammonium carbonate have a positive system entropy change?

    • Precipitate forms
    • Liquid is frozen
    • Heat is absorbed
    • Gas is produced

  16. What is dStotal for an exothermic reaction with dH = -92 kJ mol-1, dSsystem = -150 J K-1 mol-1 and T = 500 K?

    • +34 J K-1 mol-1
    • +334 J K-1 mol-1
    • -34 J K-1 mol-1
    • +184 J K-1 mol-1

  17. Which thermodynamic quantity determines whether a chemical reaction is feasible under standard conditions?

    • System entropy only
    • Activation energy
    • Total entropy change
    • Enthalpy change only

  18. For a reaction with ΔH = +50 kJ mol⁻¹ and ΔSsystem = +200 J K⁻¹ mol⁻¹, above what temperature is it feasible?

    • 250 K
    • 100 K
    • 500 K
    • 400 K

  19. What is dSsurroundings for an endothermic reaction with dH = +50 kJ mol-1 at 298 K?

    • -168 J K-1 mol-1
    • -50 J K-1 mol-1
    • +168 J K-1 mol-1
    • +50 J K-1 mol-1

  20. Which requirement must be met for a chemical reaction to be feasible?

    • ΔH is negative
    • ΔSsystem is positive
    • ΔStotal is positive
    • ΔSsurroundings is zero

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