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Principles of Chemical Equilibrium · CAPE Chemistry Unit 1

64 past-paper questions on Principles of Chemical Equilibrium, part of Kinetics and Equilibria, from every CAPE Chemistry Unit 1 paper on Quelpr.

Practise Principles of Chemical Equilibrium
  1. 4(a)5 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Describe the characteristic features of a dynamic equilibrium system, and explain which features are demonstrated in Figure 2.
  2. 4(b)(i)3 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Explain what is meant by the equilibrium terms Kc, Ka, and Kp.
  3. 4(b)(ii)2 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Write the equilibrium constant expression Kc for the esterification reaction: C2H5OH(l) + CH3COOH(l) <=> CH3COOC2H5(l) + H2O(l).
  4. 4(b)(iii)5 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Complete the missing initial and equilibrium concentration values in Table 3 for the esterification system.
  5. 4(b)(iv)2 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Calculate the value of Kc using the concentrations from Table 3.
  6. 4(c)(i)1 mark· CAPE Chemistry Unit 1 · 2005 · Paper 2Write the equilibrium constant expression for the reaction: 2SO2(g) + O2(g) <=> 2SO3(g).
  7. 4(c)(ii)2 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Explain what a very small equilibrium constant indicates about the reaction mixture, and suggest how industrial sulfuric acid production remains commercially viable.
  8. 2(c)(i)3 marks· CAPE Chemistry Unit 1 · 2021 · Paper 2Calculate the number of moles of iodine and the number of moles of hydrogen iodide in the equilibrium mixture.
  9. 2(c)(ii)1 mark· CAPE Chemistry Unit 1 · 2021 · Paper 2Write an expression for Kc for the equilibrium 2HI(g) <=> H2(g) + I2(g).
  10. 2(c)(iii)2 marks· CAPE Chemistry Unit 1 · 2021 · Paper 2Calculate the value of Kc at 700 K for the equilibrium 2HI(g) <=> H2(g) + I2(g).
  11. 2(c)(iv)1 mark· CAPE Chemistry Unit 1 · 2021 · Paper 2Calculate the value of Kc at 700 K for the equilibrium reaction H2(g) + I2(g) <=> 2HI(g).
  12. 2(a)(i)2 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2Explain the term 'dynamic equilibrium'.
  13. 2(a)(ii)1 mark· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2State what is observed when dynamic equilibrium is reached in the reaction above.
  14. 2(a)(iii)1 mark· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2State Le Chatelier's Principle.
  15. 2(a)(iv)1 mark· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2Write the expression for K_p for the reaction above.
  16. 2(a)(v)2 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2In the space provided, draw a graph to show how the concentrations of N₂O₄(g) and NO₂(g) are expected to change as the reaction proceeds towards equilibrium.
  17. 2(a)(vi)2 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2Account for the shape of the graph drawn in (a)(v).
  18. 2(a)(vii)2 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2State what is observed when the sealed tube is cooled to 0 °C. Outline the reason for what is observed.
  19. 2(a)2 marks· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2What is meant by the term 'dynamic equilibrium'?
  20. 2(b)(i)1 mark· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2Write an expression for the equilibrium constant of the reverse reaction.
  21. 2(b)(ii)1 mark· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2State the numerical value of the equilibrium constant for the reverse reaction based on the expression in (b)(i).
  22. 2(c)2 marks· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2State Le Chatelier's principle.
  23. 2(d)(i)2 marks· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2Use Le Chatelier's principle to predict and explain the effect of increasing the pressure on Equilibrium A.
  24. 2(d)(ii)2 marks· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2Use Le Chatelier's principle to predict and explain the effect of decreasing the temperature on Equilibrium A.
  25. 2(d)(iii)2 marks· CAPE Chemistry Unit 1 · May/June 2024 · Paper 2Use Le Chatelier's principle to predict and explain the effect of increasing [H^+(aq)] on Equilibrium B.
  26. 2(a)(i)4 marks· CAPE Chemistry Unit 1 · May/June 2025 · Paper 2Describe the FOUR characteristic features of this dynamic equilibrium.
  27. 2(a)(ii)2 marks· CAPE Chemistry Unit 1 · May/June 2025 · Paper 2Write a balanced chemical equation to represent the reaction described in 2(a) above.
  28. 2(a)(iii)3 marks· CAPE Chemistry Unit 1 · May/June 2025 · Paper 2Calculate the Kp value of the equilibrium mixture.
  29. 4(a)(i)4 marks· Chemistry · Unit 1 Q4 4(a)(i)Describe the features of a chemical system in a state of dynamic equilibrium.
  30. 4(a)(ii)1 mark· Chemistry · Unit 1 Q4 4(a)(ii)Define the term 'equilibrium constant'.
  31. 4(a)(iii)5 marks· Chemistry · Unit 1 Q4 4(a)(iii)Describe and explain, with reference to changes in colour, the observations made when hydrogen gas is reacted with iodine gas at constant temperature until equilibrium is achieved.
  32. 4(a)(iv)a)3 marks· Chemistry · Unit 1 Q4 4(a)(iv)a)Use the information in Table 3 and the equation in (a) (iii) above to calculate the number of moles of hydrogen reacting.
  33. 4(a)(iv)b)3 marks· Chemistry · Unit 1 Q4 4(a)(iv)b)Complete the table by inserting the equilibrium concentrations of I2 and HI.
  34. 4(a)(v)2 marks· Chemistry · Unit 1 Q4 4(a)(v)Write an equation for Kp for the reaction in (iii) above.
  35. 5(a)2 marks· Chemistry · Unit 1 Q5 5(a)State Le Chatelier's Principle.
  36. 5(a)(i)4 marks· Chemistry · Unit 1 Q5 5(a)(i)State FOUR characteristics of a reaction in 'dynamic equilibrium'.
  37. 5(a)(i)3 marks· Chemistry · Unit 1 Q5 5(a)(i)Copy and complete Table 3 to show the type of equilibrium for the selected equilibrium systems.
  38. 5(a)(i)1 mark· Chemistry · Unit 1 Q5 5(a)(i)Why is chemical equilibrium referred to as dynamic?
  39. 5(a)(ii)2 marks· Chemistry · Unit 1 Q5 5(a)(ii)State TWO characteristics of the equilibrium represented by System 1 in Table 3.
  40. 5(a)(ii)3 marks· Chemistry · Unit 1 Q5 5(a)(ii)State THREE characteristics of a chemical system at equilibrium.
  41. 5(a)(ii)2 marks· Chemistry · Unit 1 Q5 5(a)(ii)Write the expression for the equilibrium constant in terms of partial pressures, Kₚ, for the reaction shown by the equation above.
  42. 5(a)(iii)2 marks· Chemistry · Unit 1 Q5 5(a)(iii)State TWO factors which would NOT affect the equilibrium of the reaction shown by the equation above.
  43. 5(b)3 marks· Chemistry · Unit 1 Q5 5(b)Define the equilibrium constant, Kc, and describe its significance to a system in dynamic equilibrium. In your response make reference to the importance of its magnitude.
  44. 5(b)(i)2 marks· Chemistry · Unit 1 Q5 5(b)(i)State the effect of EACH of the following on the equilibrium position of the reaction in Equation 1: An increase in pressure
  45. 5(b)(i)1 mark· Chemistry · Unit 1 Q5 5(b)(i)Write the expression for the equilibrium constant.
  46. 5(b)(i)2 marks· Chemistry · Unit 1 Q5 5(b)(i)Describe the effect of decreasing the temperature on the equilibrium of the reaction
  47. 5(b)(ii)2 marks· Chemistry · Unit 1 Q5 5(b)(ii)State the effect of EACH of the following on the equilibrium position of the reaction in Equation 1: An increase in temperature
  48. 5(b)(ii)1 mark· Chemistry · Unit 1 Q5 5(b)(ii)What deduction can be made when the equilibrium constant is much greater than 1?
  49. 5(b)(ii)2 marks· Chemistry · Unit 1 Q5 5(b)(ii)Describe the effect of decreasing the temperature on the value of Kₚ.
  50. 5(c)3 marks· Chemistry · Unit 1 Q5 5(c)When 0.5 mol of hydrogen and 0.5 mol of iodine are allowed to reach equilibrium in a 1.00 dm³ flask at 500 °C and 1.01 × 10⁵ N m⁻², the amount of hydrogen iodide at equilibrium is 0.78 mol. Calculate Kₚ at 500 °C if the…
  51. 5(c)(i)6 marks· Chemistry · Unit 1 Q5 5(c)(i)Calculate the equilibrium concentration of EACH gas, at the same temperature.
  52. 5(c)(i)4 marks· Chemistry · Unit 1 Q5 5(c)(i)When SO2 and O2 are mixed in a 2 : 1 ratio at 303 K the total equilibrium pressure of the system is 101.3 kPa. Calculate Kp at 303 K for the reaction in Equation 1, if at equilibrium the number of moles of SO2, O2 and…
  53. 5(c)(i)2 marks· Chemistry · Unit 1 Q5 5(c)(i)Explain why the white precipitate, BiOCl, disappears on the addition of aqueous HCl to the equilibrium mixture.
  54. 5(c)(ii)1 mark· Chemistry · Unit 1 Q5 5(c)(ii)Comment on the value for Kp at 695 K for the reaction in Equation 1.
  55. 5(c)(ii)1 mark· Chemistry · Unit 1 Q5 5(c)(ii)Using Le Chatelier's principle, describe the effect, on the equilibrium position, of decreasing the volume of the container.
  56. 5(c)(ii)3 marks· Chemistry · Unit 1 Q5 5(c)(ii)Explain what would be observed if a large volume of water was added to the equilibrium mixture.
  57. 5(c)(iii)1 mark· Chemistry · Unit 1 Q5 5(c)(iii)Describe the effect on the equilibrium constant, Kc, of increasing the temperature of the reaction.
  58. 5(d)3 marks· Chemistry · Unit 1 Q5 5(d)Calculate the concentration of Cl2 in the mixture.
  59. 6(a)(ii)2 marks· Chemistry · Unit 1 Q6 6(a)(ii)State and explain the principle on which the reaction in Figure 1 is based.
  60. 6(b)(i)3 marks· Chemistry · Unit 1 Q6 6(b)(i)Using the information in Figure 1, account for the toxic effect of carbon monoxide at high concentrations.
  61. 6(b)(ii)2 marks· Chemistry · Unit 1 Q6 6(b)(ii)Suggest a treatment for a patient suffering from overexposure to carbon monoxide and give a reason for your suggestion.
  62. 211 mark· Chemistry · Unit 1 Q21 21Which of the following is the value of the equilibrium constant K?
  63. 221 mark· Chemistry · Unit 1 Q22 22The value of Kₚ for the equilibrium reaction H₂(g) + I₂(g) ⇌ 2HI(g) at 444 °C and 1 atm pressure is 50. What is the value of Kₚ if the pressure is changed to 2 atm and the temperature remains the same?
  64. 231 mark· Chemistry · Unit 1 Q23 23Equilibrium is established in the reaction X(aq) + Y(aq) ⇌ Z(aq). If the equilibrium concentrations are [X] = 0.2 mol dm⁻³, [Y] = 0.3 mol dm⁻³ and [Z] = 0.6 mol dm⁻³, which of the following values is correct for the…

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