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Entropy and feasibility of reactions: Eduqas A‑Level Chemistry questions

Every Eduqas A-Level Chemistry exam question on PI4.2 Entropy and feasibility of reactions, 2016–2025, with its mark scheme and examiner’s report.

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1,513 questions

  1. Q11(b)(ii)

    June 2025 · Component 1

    5 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    June 2025 Component 1, question 11(b)(ii): Heating calcium hydroxide can cause it to decompose and form calcium oxide. Ca(OH)2(s) CaO(s) + H2O(g) I. The entropy change for this reaction is 153 J K–1 mol–

  2. Q13(d)(iii)

    June 2024 · Component 1

    2 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    June 2024 Component 1, question 13(d)(iii): Calculate the standard entropy change for this reaction. [2] ΔSθ = J K–1 mol–1

  3. Q13(d)(iv)

    June 2024 · Component 1

    2 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    June 2024 Component 1, question 13(d)(iv): Calculate the minimum temperature required for this thermal decomposition. [2] T = °C

  4. Q11(d)(iii)

    Autumn 2021 · Component 1

    1 markPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    Autumn 2021 Component 1, question 11(d)(iii): Give a reason why the standard entropy of chlorine is the greatest of all four substances listed. [1]

  5. Q11(d)(iv)

    Autumn 2021 · Component 1

    4 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    Autumn 2021 Component 1, question 11(d)(iv): Use the values in the table to show that the student is incorrect and that the disproportionation reaction will not occur at any temperature for the substances

  6. Q12(b)

    Autumn 2021 · Component 1

    3 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    Autumn 2021 Component 1, question 12(b): One method of making ethanoic acid is by the carbonylation of methanol. CH3COOH(l) ΔGθ = –88 kJ mol–1 CH3OH(l) + CO(g) ΔHθ = –137 kJ mol–1 Calculate the standa

  7. Q8(d)(i)

    Autumn 2020 · Component 1

    4 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    Autumn 2020 Component 1, question 8(d)(i): Heating magnesium carbonate causes the compound to decompose forming magnesium oxide and carbon dioxide. The equation for this process is: MgCO3(s) MgO(s) + CO2

  8. Q8(d)(ii)

    Autumn 2020 · Component 1

    1 markPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    Autumn 2020 Component 1, question 8(d)(ii): The element calcium lies below magnesium in Group 2. Suggest a value for the minimum temperature required for the thermal decomposition of CaCO3. Give a reason

  9. Q13(b)(ii)

    June 2019 · Component 1

    7 marksPI4.2 Entropy and feasibility of reactionsC2.2 Thermochemistry
    The whole paper ↗
    June 2019 Component 1, question 13(b)(ii): One method of producing hydrazine is to oxidise ammonia using an appropriate oxidising agent, such as hydrogen peroxide. 2NH3(g) + H2O2(l) NH2NH2(l) + 2H2O(l) Δ

  10. Q9(a)(iii)

    June 2018 · Component 1

    5 marksPI4.1 Enthalpy changes for solids and solutionsPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    June 2018 Component 1, question 9(a)(iii): The standard enthalpy change of solution of CsCl is +18 kJ mol–1 and the enthalpy of hydration of a chloride ion is –364 kJ mol–1. I. Calculate the enthalpy cha

  11. Q8

    June 2017 · Component 1

    2 marksPI4.2 Entropy and feasibility of reactions
    The whole paper ↗
    June 2017 Component 1, question 8: Explain why solid sodium chloride can dissolve in water even though the process is endothermic. [2]
All 11 questions on Entropy and feasibility of reactions, as a list
  1. June 2025, Component 1, Q11(b)(ii) (5 marks): Heating calcium hydroxide can cause it to decompose and form calcium oxide. Ca(OH)2(s) CaO(s) + H2O(g) I. The entropy change for this reaction is 153 J K–1 mol–
  2. June 2024, Component 1, Q13(d)(iii) (2 marks): Calculate the standard entropy change for this reaction. [2] ΔSθ = J K–1 mol–1
  3. June 2024, Component 1, Q13(d)(iv) (2 marks): Calculate the minimum temperature required for this thermal decomposition. [2] T = °C
  4. Autumn 2021, Component 1, Q11(d)(iii) (1 mark): Give a reason why the standard entropy of chlorine is the greatest of all four substances listed. [1]
  5. Autumn 2021, Component 1, Q11(d)(iv) (4 marks): Use the values in the table to show that the student is incorrect and that the disproportionation reaction will not occur at any temperature for the substances
  6. Autumn 2021, Component 1, Q12(b) (3 marks): One method of making ethanoic acid is by the carbonylation of methanol. CH3COOH(l) ΔGθ = –88 kJ mol–1 CH3OH(l) + CO(g) ΔHθ = –137 kJ mol–1 Calculate the standa
  7. Autumn 2020, Component 1, Q8(d)(i) (4 marks): Heating magnesium carbonate causes the compound to decompose forming magnesium oxide and carbon dioxide. The equation for this process is: MgCO3(s) MgO(s) + CO2
  8. Autumn 2020, Component 1, Q8(d)(ii) (1 mark): The element calcium lies below magnesium in Group 2. Suggest a value for the minimum temperature required for the thermal decomposition of CaCO3. Give a reason
  9. June 2019, Component 1, Q13(b)(ii) (7 marks): One method of producing hydrazine is to oxidise ammonia using an appropriate oxidising agent, such as hydrogen peroxide. 2NH3(g) + H2O2(l) NH2NH2(l) + 2H2O(l) Δ
  10. June 2018, Component 1, Q9(a)(iii) (5 marks): The standard enthalpy change of solution of CsCl is +18 kJ mol–1 and the enthalpy of hydration of a chloride ion is –364 kJ mol–1. I. Calculate the enthalpy cha
  11. June 2017, Component 1, Q8 (2 marks): Explain why solid sodium chloride can dissolve in water even though the process is endothermic. [2]

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