plumiReversible reactions and equilibria: Edexcel International GCSE Chemistry questions
Every Edexcel International GCSE Chemistry exam question on Reversible reactions and equilibria (specification points 3.17–3.22), 2019–2025, with its mark scheme and examiner’s report.
Paper
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Exam
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Calculations
Q6(a)(ii)
The whole paper ↗Q6(b)(i)
The whole paper ↗Q6(b)(ii)
The whole paper ↗Q7(a)(i)
The whole paper ↗Q7(a)(ii)
The whole paper ↗Q7(b)
The whole paper ↗Q7(c)(i)
The whole paper ↗Q7(c)(ii)
The whole paper ↗Q7(a)(i)
The whole paper ↗Q7(a)(ii)
The whole paper ↗Q7(a)(iii)
The whole paper ↗Q7(a)(iv)
The whole paper ↗Q12(c)(i)
The whole paper ↗Q6(b)
The whole paper ↗Q5(c)(ii)
The whole paper ↗Q5(c)(iii)
The whole paper ↗Q7(a)(i)
The whole paper ↗Q7(b)(i)
The whole paper ↗Q7(b)(ii)
The whole paper ↗Q3(b)(iv)
The whole paper ↗
All 42 questions on Reversible reactions and equilibria, as a list
- June 2025, Paper 2, Q6(a)(ii) (1 mark): State what the symbol represents. (1)
- June 2025, Paper 2, Q6(b)(i) (2 marks): The temperature of the reaction mixture is increased to 600°C, but the pressure is kept at 2 atm. Explain the effect, if any, on the yield of hydrogen iodide at
- June 2025, Paper 2, Q6(b)(ii) (2 marks): The pressure of the reaction mixture is decreased to 1 atm but the temperature is kept at 500°C. Explain the effect, if any, on the yield of hydrogen iodide at
- June 2024 (R), Paper 2, Q7(a)(i) (2 marks): The pressure on an equilibrium mixture of the three gases is decreased. All the other conditions are kept the same. Predict the effect of this change on the yie
- June 2024 (R), Paper 2, Q7(a)(ii) (2 marks): Predict the effect of adding a catalyst on the yield of ethanol at equilibrium, giving a reason for your answer. (2)
- June 2023, Paper 2, Q7(b) (2 marks): Explain the effect, if any, on the yield of hydrogen at equilibrium when a nickel catalyst is used. (2)
- June 2023, Paper 2, Q7(c)(i) (2 marks): The temperature of the reaction mixture is reduced to 600 °C, but the pressure is kept at 5 atmospheres. Explain the effect on the yield of hydrogen at equilibr
- June 2023, Paper 2, Q7(c)(ii) (2 marks): The pressure of the reaction mixture is reduced to 4 atmospheres, but the temperature is kept at 700 °C. Explain the effect on the yield of hydrogen at equilibr
- June 2023 (R), Paper 2, Q7(a)(i) (2 marks): Give two characteristics of a reaction at dynamic equilibrium. (2) 1 2
- June 2023 (R), Paper 2, Q7(a)(ii) (1 mark): Give a reason why adding a catalyst does not affect the yield of methanol. (1)
- June 2023 (R), Paper 2, Q7(a)(iii) (2 marks): The temperature of the reaction mixture is decreased at constant pressure. Explain the effect of this change on the yield of methanol. (2)
- June 2023 (R), Paper 2, Q7(a)(iv) (2 marks): The pressure of the reaction mixture is increased at constant temperature. Explain the effect of this change on the yield of methanol. (2)
- January 2023, Paper 1, Q12(c)(i) (1 mark): Give the meaning of the symbol (1)
- January 2023, Paper 2, Q6(b) (2 marks): The reaction mixture is kept in a sealed container until dynamic equilibrium is reached. State what is meant by the term dynamic equilibrium. (2)
- June 2022, Paper 2, Q5(c)(ii) (1 mark): State what is meant by the symbol. (1)
- June 2022, Paper 2, Q5(c)(iii) (1 mark): When this reaction occurs in a sealed container, the reaction can reach dynamic equilibrium. Give one characteristic of a reaction at dynamic equilibrium. (1)
- June 2022 (R), Paper 2, Q7(a)(i) (1 mark): State what the symbol represents. (1)
- June 2022 (R), Paper 2, Q7(b)(i) (2 marks): The reaction mixture is kept at a pressure of 200 atmospheres, but the temperature is increased to 550 °C. Explain the effect of this change on the yield of amm
- June 2022 (R), Paper 2, Q7(b)(ii) (2 marks): The reaction mixture is kept at a temperature of 450 °C, but the pressure is increased to 300 atmospheres. Explain the effect of this change on the yield of amm
- January 2022, Paper 2, Q3(b)(iv) (1 mark): Suggest why the student’s method is not suitable for determining the solubility of hydrated copper(II) sulfate. (1)
- January 2022, Paper 2, Q7(c)(i) (2 marks): Describe what is meant by dynamic equilibrium. (2)
- January 2022, Paper 2, Q7(c)(ii) (2 marks): Explain why adding a catalyst does not change the position of equilibrium. (2)
- January 2022 (R), Paper 2, Q5(b)(ii) (1 mark): The temperature is kept constant. Give a reason why increasing the pressure would increase the yield of sulfur trioxide. (1)
- January 2022 (R), Paper 2, Q5(b)(iii) (1 mark): Suggest why it is not necessary to increase the pressure in stage 2. (1)
- November 2021, Paper 2, Q7(a)(i) (2 marks): The pressure of an equilibrium mixture of the three gases is increased. Predict the effect of this change on the yield of hydrogen iodide at equilibrium, giving
- November 2021, Paper 2, Q7(a)(ii) (2 marks): A catalyst is added to an equilibrium mixture of the three gases. Predict the effect of the catalyst on the yield of hydrogen iodide at equilibrium, giving a re
- January 2021 (R), Paper 2, Q8(b) (2 marks): In industry, ammonia is produced from nitrogen and hydrogen. The equation for this reaction is N2(g) + 3H2(g) 2NH3(g) In a sealed container, the reaction can
- January 2021 (R), Paper 2, Q8(c) (2 marks): The graph shows the percentage yield of ammonia at equilibrium for different temperatures and pressures. 80 350 °C 70 60 450 °C 50 Percentage yield of ammonia a
- November 2020, Paper 2, Q7(b)(i) (2 marks): Predict the effect on the yield of CO(g) at equilibrium when the temperature is increased without changing the pressure. Give a reason for your answer. (2)
- November 2020, Paper 2, Q7(b)(ii) (2 marks): Predict the effect on the yield of CO(g) at equilibrium when the pressure is increased without changing the temperature. Give a reason for your answer. (2)
- November 2020 (R), Paper 2, Q7(c)(iii) (2 marks): When this reaction takes place in a sealed container, the reaction can reach dynamic equilibrium. Give two characteristics of a reaction at dynamic equilibrium.
- January 2020, Paper 1, Q10(a)(ii) (1 mark): Give the meaning of the symbol (1)
- January 2020 (R), Paper 1, Q4(c) (1 mark): The equation shows the thermal decomposition of ammonium chloride. NH4Cl(s) U NH3(g) + HCl(g) State what the U symbol indicates about this reaction. (1)
- January 2020 (R), Paper 2, Q7(b)(i) (2 marks): This reaction is in dynamic equilibrium. Give two features of a reaction in dynamic equilibrium. (2) 1 2
- January 2020 (R), Paper 2, Q7(b)(ii) (2 marks): When the equilibrium mixture is heated, the yield of ethanol decreases. Explain whether the forward reaction is exothermic or endothermic. (2)
- June 2019, Paper 1, Q5(c)(i) (1 mark): Give a chemical equation for this reaction. (1)
- June 2019, Paper 2, Q7(a) (2 marks): Explain what is meant by the term dynamic equilibrium. (2)
- June 2019, Paper 2, Q7(b)(i) (2 marks): The pressure of the gas in the syringe is increased by pushing in the piston. The mixture is then allowed to reach a new equilibrium at the same temperature as
- June 2019, Paper 2, Q7(b)(ii) (1 mark): A student suggests that the new equilibrium mixture would be lighter in colour than the original equilibrium mixture, as there is now less NO2 present. Suggest
- June 2019 (R), Paper 2, Q7(a) (1 mark): What does the symbol represent? (1)
- June 2019 (R), Paper 2, Q7(b)(i) (2 marks): The mixture of methane and steam is heated to a temperature greater than 700 °C but the pressure is kept at 5 atmospheres. Predict the effect of this change on
- June 2019 (R), Paper 2, Q7(b)(ii) (2 marks): The mixture of methane and steam is kept at the same temperature of 700 °C but the pressure is increased to more than 5 atmospheres. Predict the effect of this
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