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Thermodynamics: AQA A‑Level Chemistry questions

Every AQA A-Level Chemistry exam question on 3.1.8 Thermodynamics, 2016–2025, with its mark scheme and examiner’s report.

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2,301 questions

  1. Q04.2

    June 2025 · Paper 1

    5 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2025 Paper 1, question 04.2: Use the equation and the data in Table 4 to calculate the temperature at which this reaction becomes feasible. [5 marks] Temperature K

  2. Q01.3

    June 2025 · Paper 3

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2025 Paper 3, question 01.3: Table 2 shows some enthalpy change data. Table 2 Enthalpy change / kJ mol–1 Enthalpy of lattice formation of potassium hydroxide –789 Enthalpy of hydration of p

  3. Q08.1

    June 2024 · Paper 1

    1 mark3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.1: Theoretical values for enthalpies of lattice dissociation can be calculated using a perfect ionic model. State the meaning of the term perfect ionic model. [1 m

  4. Q08.2

    June 2024 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.2: Enthalpies of lattice dissociation can also be obtained from Born–Haber cycles. Figure 3 shows an incomplete Born–Haber cycle for the formation of sodium oxide.

  5. Q08.3

    June 2024 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.3: Table 4 shows some enthalpy changes. Table 4 Enthalpy change ΔH / kJ mol–1 Enthalpy of atomisation of oxygen +248 Enthalpy of atomisation of sodium +109 Enthalp

  6. Q08.4

    June 2024 · Paper 1

    1 mark3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.4: Explain why the second electron affinity of oxygen has a positive value. [1 mark]

  7. Q08.5

    June 2024 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.5: Explain why the enthalpy of lattice dissociation for sodium oxide is greater than the enthalpy of lattice dissociation for sodium chloride. [2 marks]

  8. Q08.6

    June 2024 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.6: Sodium chloride dissolves in water. Table 5 shows some more enthalpy changes. Table 5 Enthalpy change ΔH / kJ mol–1 Enthalpy of hydration for Cl– ions –364 Enth

  9. Q08.7

    June 2024 · Paper 1

    1 mark3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.7: Give a reason why data books do not contain a value for the enthalpy of solution of sodium oxide. [1 mark]

  10. Q08.8

    June 2024 · Paper 1

    3 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2024 Paper 1, question 08.8: Calculate the temperature, in °C, at which this reaction becomes feasible. NaCl(s) → Na(s) + 1 2 Cl2(g) ΔH = +411 kJ mol–1 ΔS = +90.1 J K–1 mol–1 [3 marks] Temp

  11. Q05.1

    June 2023 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2023 Paper 1, question 05.1: Table 2 shows some enthalpy change data. Table 2 Enthalpy change / kJ mol–1 Ca2+(g) → Ca2+(aq) –1650 Cl–(g) → Cl–(aq) –364 Ca2+(g) + 2 Cl– (g) → CaCl2(s) –2237

  12. Q05.2

    June 2023 · Paper 1

    1 mark3.1.8 Thermodynamics
    The whole paper ↗
    June 2023 Paper 1, question 05.2: Use your answer to Question 05.1 to deduce how the temperature changes when calcium chloride dissolves in water. [1 mark]

  13. Q05.3

    June 2023 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2023 Paper 1, question 05.3: Explain why the enthalpy of hydration of fluoride ions is more negative than the enthalpy of hydration of chloride ions. [2 marks]

  14. Q05.4

    June 2023 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2023 Paper 1, question 05.4: Figure 2 shows an incomplete Born–Haber cycle for calcium chloride. Figure 2 Complete the Born–Haber cycle by writing the formulas of the missing species on eac

  15. Q05.5

    June 2023 · Paper 1

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2023 Paper 1, question 05.5: Table 3 shows some enthalpy change data. Table 3 Enthalpy change / kJ mol–1 Enthalpy of atomisation of calcium +193 First ionisation energy of calcium +590 Enth

  16. Q05.7

    June 2023 · Paper 1

    6 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2023 Paper 1, question 05.7: Table 4 shows lattice enthalpies based on a perfect ionic model and lattice enthalpies from Born–Haber cycles for three metal chlorides. Table 4 Lattice enthalp

  17. Q01.1

    June 2022 · Paper 3

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2022 Paper 3, question 01.1: Define the term enthalpy of lattice dissociation. [2 marks]

  18. Q01.2

    June 2022 · Paper 3

    3 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2022 Paper 3, question 01.2: The enthalpy of solution for ammonium nitrate is the enthalpy change for the reaction shown. NH4NO3(s) + aq → NH4+(aq) + NO3−(aq) ∆H = +26 kJ mol−1 Table 1 NH4+

  19. Q01.7

    June 2022 · Paper 3

    4 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2022 Paper 3, question 01.7: Table 3 shows some entropy data at 298 K Table 3 Entropy S / J K 1 mol 1 NH4NO3(s) 151 NH4+(aq) 113 NO3−(aq) 146 Calculate a value for the Gibbs free-energy cha

  20. Q01.8

    June 2022 · Paper 3

    2 marks3.1.8 Thermodynamics
    The whole paper ↗
    June 2022 Paper 3, question 01.8: Ammonium nitrate decomposes as shown. NH4NO3(s) → N2 (g) + 1 2 O2 (g) + 2 H2 O (g) ∆H = +123 kJ mol−1 The entropy change (∆S) for this reaction is +144 J K–1 mo
All 57 questions on Thermodynamics, as a list
  1. June 2025, Paper 1, Q04.2 (5 marks): Use the equation and the data in Table 4 to calculate the temperature at which this reaction becomes feasible. [5 marks] Temperature K
  2. June 2025, Paper 3, Q01.3 (2 marks): Table 2 shows some enthalpy change data. Table 2 Enthalpy change / kJ mol–1 Enthalpy of lattice formation of potassium hydroxide –789 Enthalpy of hydration of p
  3. June 2024, Paper 1, Q08.1 (1 mark): Theoretical values for enthalpies of lattice dissociation can be calculated using a perfect ionic model. State the meaning of the term perfect ionic model. [1 m
  4. June 2024, Paper 1, Q08.2 (2 marks): Enthalpies of lattice dissociation can also be obtained from Born–Haber cycles. Figure 3 shows an incomplete Born–Haber cycle for the formation of sodium oxide.
  5. June 2024, Paper 1, Q08.3 (2 marks): Table 4 shows some enthalpy changes. Table 4 Enthalpy change ΔH / kJ mol–1 Enthalpy of atomisation of oxygen +248 Enthalpy of atomisation of sodium +109 Enthalp
  6. June 2024, Paper 1, Q08.4 (1 mark): Explain why the second electron affinity of oxygen has a positive value. [1 mark]
  7. June 2024, Paper 1, Q08.5 (2 marks): Explain why the enthalpy of lattice dissociation for sodium oxide is greater than the enthalpy of lattice dissociation for sodium chloride. [2 marks]
  8. June 2024, Paper 1, Q08.6 (2 marks): Sodium chloride dissolves in water. Table 5 shows some more enthalpy changes. Table 5 Enthalpy change ΔH / kJ mol–1 Enthalpy of hydration for Cl– ions –364 Enth
  9. June 2024, Paper 1, Q08.7 (1 mark): Give a reason why data books do not contain a value for the enthalpy of solution of sodium oxide. [1 mark]
  10. June 2024, Paper 1, Q08.8 (3 marks): Calculate the temperature, in °C, at which this reaction becomes feasible. NaCl(s) → Na(s) + 1 2 Cl2(g) ΔH = +411 kJ mol–1 ΔS = +90.1 J K–1 mol–1 [3 marks] Temp
  11. June 2023, Paper 1, Q05.1 (2 marks): Table 2 shows some enthalpy change data. Table 2 Enthalpy change / kJ mol–1 Ca2+(g) → Ca2+(aq) –1650 Cl–(g) → Cl–(aq) –364 Ca2+(g) + 2 Cl– (g) → CaCl2(s) –2237
  12. June 2023, Paper 1, Q05.2 (1 mark): Use your answer to Question 05.1 to deduce how the temperature changes when calcium chloride dissolves in water. [1 mark]
  13. June 2023, Paper 1, Q05.3 (2 marks): Explain why the enthalpy of hydration of fluoride ions is more negative than the enthalpy of hydration of chloride ions. [2 marks]
  14. June 2023, Paper 1, Q05.4 (2 marks): Figure 2 shows an incomplete Born–Haber cycle for calcium chloride. Figure 2 Complete the Born–Haber cycle by writing the formulas of the missing species on eac
  15. June 2023, Paper 1, Q05.5 (2 marks): Table 3 shows some enthalpy change data. Table 3 Enthalpy change / kJ mol–1 Enthalpy of atomisation of calcium +193 First ionisation energy of calcium +590 Enth
  16. June 2023, Paper 1, Q05.7 (6 marks): Table 4 shows lattice enthalpies based on a perfect ionic model and lattice enthalpies from Born–Haber cycles for three metal chlorides. Table 4 Lattice enthalp
  17. June 2022, Paper 3, Q01.1 (2 marks): Define the term enthalpy of lattice dissociation. [2 marks]
  18. June 2022, Paper 3, Q01.2 (3 marks): The enthalpy of solution for ammonium nitrate is the enthalpy change for the reaction shown. NH4NO3(s) + aq → NH4+(aq) + NO3−(aq) ∆H = +26 kJ mol−1 Table 1 NH4+
  19. June 2022, Paper 3, Q01.7 (4 marks): Table 3 shows some entropy data at 298 K Table 3 Entropy S / J K 1 mol 1 NH4NO3(s) 151 NH4+(aq) 113 NO3−(aq) 146 Calculate a value for the Gibbs free-energy cha
  20. June 2022, Paper 3, Q01.8 (2 marks): Ammonium nitrate decomposes as shown. NH4NO3(s) → N2 (g) + 1 2 O2 (g) + 2 H2 O (g) ∆H = +123 kJ mol−1 The entropy change (∆S) for this reaction is +144 J K–1 mo
  21. November 2021, Paper 1, Q01.2 (3 marks): Complete Figure 1 by writing the formulas, including state symbols, of the appropriate species on each of the three blank lines. [3 marks]
  22. November 2021, Paper 1, Q01.3 (2 marks): Table 1 shows some enthalpy data. Table 1 Enthalpy change / kJ mol–1 Enthalpy of formation of calcium chloride –795 Enthalpy of atomisation of calcium +193 Firs
  23. November 2021, Paper 1, Q01.4 (1 mark): Magnesium chloride dissolves in water. Give an equation, including state symbols, to represent the process that occurs when the enthalpy of solution of magnesiu
  24. November 2021, Paper 1, Q01.5 (2 marks): Table 2 shows some enthalpy data. Table 2 Enthalpy change / kJ mol–1 Enthalpy of lattice dissociation of MgCl2 +2493 Enthalpy of hydration of Mg2+(g) –1920 Enth
  25. November 2021, Paper 1, Q01.6 (2 marks): The enthalpy of hydration of Ca2+(g) is –1650 kJ mol–1 Suggest why this value is less exothermic than that of Mg2+(g) [2 marks]
  26. November 2021, Paper 1, Q07.1 (1 mark): Explain why the standard entropy value for carbon dioxide is greater than that for carbon. [1 mark]
  27. November 2021, Paper 1, Q07.2 (1 mark): State the temperature at which the standard entropy of aluminium is 0 J K–1 mol–1 [1 mark]
  28. November 2021, Paper 1, Q07.3 (7 marks): Use the equation and the data in Table 7 to calculate the minimum temperature, in K, at which this reaction becomes feasible. [7 marks] Minimum temperature K
  29. November 2020, Paper 1, Q01.1 (3 marks): Figure 1 shows a Born–Haber cycle for the formation of strontium chloride, SrCl2 Figure 1 Table 1 shows some thermodynamic data. Table 1 Enthalpy change / kJ mo
  30. November 2020, Paper 1, Q01.2 (1 mark): Draw a line from each substance to the enthalpy of lattice formation of that substance. [1 mark] Substance Enthalpy of lattice formation / kJ mol–1 MgCl2 –2018
  31. November 2020, Paper 1, Q01.3 (1 mark): State why there is a difference between the theoretical and experimental values. [1 mark]
  32. November 2020, Paper 1, Q01.4 (2 marks): Table 3 shows enthalpy of hydration values for ions of some Group 1 elements. Table 3 Li+(g) Na+(g) K+(g) Enthalpy of hydration / kJ mol–1 –519 –406 –322 Explai
  33. November 2020, Paper 1, Q01.5 (3 marks): Calcium bromide dissolves in water. Table 4 shows some enthalpy data. Table 4 Enthalpy change / kJ mol–1 Enthalpy of solution of calcium bromide –110 Enthalpy o
  34. November 2020, Paper 1, Q10.1 (6 marks): Use the equation and the data in Table 5 to calculate the Gibbs free-energy change (ΔG), in kJ mol–1, for this reaction at 890 K [6 marks] ΔG kJ mol–1
  35. November 2020, Paper 1, Q10.2 (4 marks): Use the values of the intercept and gradient from the graph in Figure 4 to calculate the enthalpy change (ΔH), in kJ mol–1, and the entropy change (ΔS), in J K–
  36. November 2020, Paper 1, Q10.3 (1 mark): State what Figure 4 shows about the feasibility of the reaction. [1 mark]
  37. June 2019, Paper 1, Q01.1 (2 marks): Complete Figure 1 by writing the formulas, including state symbols, of the appropriate species on each of the two blank lines. [2 marks]
  38. June 2019, Paper 1, Q01.2 (2 marks): Use Figure 1 and the data in Table 1 to calculate the standard enthalpy of atomisation of iodine. [2 marks] Standard enthalpy of atomisation of iodine kJ mol-1
  39. June 2019, Paper 1, Q01.3 (1 mark): The enthalpy of lattice formation for caesium iodide in Table 1 is a value obtained by experiment. The value obtained by calculation using the perfect ionic mod
  40. June 2019, Paper 1, Q01.4 (4 marks): Use data from Table 2 to show that this reaction is not feasible at 298 K CsI(s) → Cs(s) + 1 2 I2(s) ∆Ho = +337 kJ mol–1 Table 2 CsI(s) Cs(s) I2(s) So / J K–1 m
  41. June 2018, Paper 1, Q01.1 (3 marks): Figure 1 shows a Born–Haber cycle for the formation of magnesium oxide. Complete Figure 1 by writing the missing symbols on the appropriate energy levels. [3 ma
  42. June 2018, Paper 1, Q01.2 (3 marks): Table 1 contains some thermodynamic data. Table 1 Enthalpy change / kJ mol–1 Enthalpy of formation for magnesium oxide –602 Enthalpy of atomisation for magnesiu
  43. June 2018, Paper 1, Q03.1 (2 marks): Calculate the entropy change for the reaction between ammonia and oxygen. [2 marks] Entropy change J K–1 mol–1
  44. June 2018, Paper 1, Q03.2 (2 marks): Calculate a value for the Gibbs free-energy change (ΔG), in kJ mol–1, for the reaction between ammonia and oxygen at 600 °C (If you were unable to obtain an ans
  45. June 2018, Paper 1, Q03.3 (2 marks): The reaction between ammonia and oxygen was carried out at a higher temperature. Explain how this change affects the value of ΔG for the reaction. [2 marks]
  46. June 2018, Paper 3, Q14 (1 mark): Which equation represents the process that occurs when the standard enthalpy of atomisation of iodine is measured? [1 mark] A I2(s)  I(g) B I2(s)  2I(g) C I2(
  47. June 2018, Paper 3, Q33 (1 mark): Lattice enthalpy values can be obtained from Born–Haber cycles and by calculations based on a perfect ionic model. Which compound shows the greatest percentage
  48. June 2017, Paper 1, Q01.1 (2 marks): Define the term enthalpy of lattice formation. [2 marks
  49. June 2017, Paper 1, Q01.2 (2 marks): Some enthalpy change data are shown in Table 1. Table 1 Enthalpy change / kJ mol−1 AgI(s) → Ag+(aq) + I–(aq) +112 Ag+(g) → Ag+(aq) −464 I–(g) → I–(aq) −293 Use
  50. June 2017, Paper 1, Q01.3 (2 marks): A calculation of the enthalpy of lattice formation of silver iodide based on a perfect ionic model gives a smaller numerical value than the value calculated in
  51. June 2017, Paper 1, Q05.1 (6 marks): Some entropy data are shown in Table 3. Table 3 Substance TiO2(s) C(s) Cl2(g) CO(g) TiCl4(l) So / J K−1 mol−1 50.2 5.70 223 198 253 Use the equation and the dat
  52. June 2017, Paper 3, Q01.4 (5 marks): Anhydrous magnesium chloride can be formed by direct reaction between its elements. Mg(s) + Cl2(g) → MgCl2(s) The free-energy change, ∆G, for this reaction vari
  53. June 2017, Paper 3, Q32 (1 mark): A reaction is exothermic and has a negative entropy change. Which statement is correct? [1 mark] A The reaction is always feasible B The reaction is feasible ab
  54. Specimen, Paper 1, Q05.1 (4 marks): Free-energy change = Units = 3
  55. Specimen, Paper 1, Q05.2 (2 marks): Temperature = K
  56. Specimen, Paper 1, Q09.3 (2 marks): Lattice enthalpy of dissociation = kJ mol –1
  57. Specimen, Paper 1, Q09.4 (2 marks): 6

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