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Energetics · CAPE Chemistry Unit 1

68 past-paper questions on Energetics, part of Fundamentals in Chemistry, from every CAPE Chemistry Unit 1 paper on Quelpr.

Practise Energetics
  1. 5(a)2 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Explain the meaning of the term enthalpy change of a reaction.
  2. 5(b)6 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Distinguish between exothermic and endothermic reactions by referring to energy profile diagrams and bond energies.
  3. 5(c)(iii)4 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Calculate the enthalpy of reaction for N2H4(l) + O2(g) -> N2(g) + 2H2O(g) (ΔH = -534 kJ mol^-1) if liquid water is formed, given the molar enthalpy of vaporization of water is 40.7 kJ mol^-1.
  4. 5(d)(i)1 mark· CAPE Chemistry Unit 1 · 2005 · Paper 2Suggest why the standard enthalpy of formation of carbon monoxide from C(s) and O2(g) cannot be determined directly by experiment.
  5. 5(d)(ii)3 marks· CAPE Chemistry Unit 1 · 2005 · Paper 2Construct an energy cycle diagram showing how standard enthalpies of combustion of carbon and carbon monoxide are used to obtain the standard enthalpy of formation of CO(g).
  6. 1(c)3 marks· CAPE Chemistry Unit 1 · May/June 2019 · Paper 2Using the bond energies from Table 1, determine the enthalpy of reaction, ΔH_r.
  7. 1(d)5 marks· CAPE Chemistry Unit 1 · May/June 2019 · Paper 2Outline an experiment to determine the heat of solution of ammonium nitrate, including a labelled diagram of the apparatus, data to be collected, and how the data collected can be used to determine the heat of solution.
  8. 1(e)(i)1 mark· CAPE Chemistry Unit 1 · May/June 2022 · Paper 2Define the term 'bond energy'.
  9. 1(e)(ii)5 marks· CAPE Chemistry Unit 1 · May/June 2022 · Paper 2Using the bond energy values in Table 2, determine the enthalpy change for the reaction: CH4(g) + 2O2(g) -> CO2(g) + 2H2O(g) Show all working.
  10. 1(f)5 marks· CAPE Chemistry Unit 1 · May/June 2022 · Paper 2Outline the experimental steps required to determine the enthalpy of neutralization reaction between 50 cm^3 of 1.00 M sodium hydroxide solution and 50 cm^3 of 1.00 M hydrochloric acid to obtain an accurate value.…
  11. 1(d)(i)2 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2State Hess' law.
  12. 1(d)(ii)6 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2Construct a Born–Haber cycle for the formation of lead (II) fluoride, PbF₂(s), showing clearly, using equations, the steps of the enthalpy changes involved.
  13. 1(d)(iii)3 marks· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2Using the data in Table 1, calculate the lattice energy of PbF₂(s).
  14. 1(e)(i)1 mark· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2State the effect of ionic charge on the magnitude of the lattice energy.
  15. 1(e)(ii)1 mark· CAPE Chemistry Unit 1 · May/June 2023 · Paper 2State the effect of ionic radius on the magnitude of the lattice energy.
  16. 1(a)3 marks· Chemistry · Unit 1 Q1 1(a)Use Hess's law to calculate the enthalpy change for the following reaction: 2Mg (s) + O2(g) → 2MgO(s)
  17. 1(a)(i)1 mark· Chemistry · Unit 1 Q1 1(a)(i)Define the term 'bond energy'.
  18. 1(a)(i)2 marks· Chemistry · Unit 1 Q1 1(a)(i)Define the term 'standard enthalpy of formation', ΔHᶠθ.
  19. 1(a)(ii)2 marks· Chemistry · Unit 1 Q1 1(a)(ii)The enthalpy of formation of both carbon monoxide and aluminium oxide cannot be determined directly by experimental means. Suggest ONE reason in EACH case for the above observation. CO: Al₂O₃:
  20. 1(a)(ii)1 mark· Chemistry · Unit 1 Q1 1(a)(ii)State the relationship between the strength of a covalent bond and its length.
  21. 1(b)4 marks· Chemistry · Unit 1 Q1 1(b)Identify FOUR errors in the assembly of the apparatus in Figure 1.
  22. 1(b)(i)1 mark· Chemistry · Unit 1 Q1 1(b)(i)Explain the reason for stirring the mixture at regular intervals.
  23. 1(b)(i)3 marks· Chemistry · Unit 1 Q1 1(b)(i)Write the enthalpy change represented by ΔH₁, ΔH₂ and ΔH₃ in Figure 1. ΔH₁ : ΔH₂ : ΔH₃ :
  24. 1(b)(ii)2 marks· Chemistry · Unit 1 Q1 1(b)(ii)Given that the initial and final temperatures are 28°C and 57°C respectively, sketch a typical graph for the results of the experiment to illustrate how the student arrived at the temperature change, ΔT, for the…
  25. 1(b)(ii)3 marks· Chemistry · Unit 1 Q1 1(b)(ii)Using bond energy values from Table 1, calculate the enthalpy change of reaction, ΔHrxn, for the equation required in (b) (i).
  26. 1(b)(ii)3 marks· Chemistry · Unit 1 Q1 1(b)(ii)Calculate the enthalpy of solution for KBr, given the following information. ΔH₁ = + 672 kJ mol⁻¹ ΔH₂ = - 656 kJ mol⁻¹
  27. 1(b)(iii)1 mark· Chemistry · Unit 1 Q1 1(b)(iii)Give the main source of error for the experiment.
  28. 1(b)(iii)1 mark· Chemistry · Unit 1 Q1 1(b)(iii)Is the reaction in (b) (i) exothermic or endothermic?
  29. 1(b)(iv)3 marks· Chemistry · Unit 1 Q1 1(b)(iv)Calculate the enthalpy change, in kJ mol⁻¹ of Mg for the reaction at constant pressure, given ΔT = 29.0°C, C = 4.20 Jg⁻¹ °C⁻¹. The density of dilute HCl is 1.0g cm⁻³.
  30. 1(b)(iv)2 marks· Chemistry · Unit 1 Q1 1(b)(iv)On the axes provided below, draw the energy-profile diagram for the reaction in (b) (i).
  31. 1(c)(i)1 mark· Chemistry · Unit 1 Q1 1(c)(i)Use the results of your calculation in (b)(iv) above to state whether the reaction is endothermic or exothermic.
  32. 1(c)(ii)4 marks· Chemistry · Unit 1 Q1 1(c)(ii)Draw a clearly labelled energy profile diagram for the reaction between magnesium and hydrochloric acid. Include on your diagram the enthalpy change for the reaction.
  33. 1(d)(i)3 marks· Chemistry · Unit 1 Q1 1(d)(i)Identify THREE errors in the above method.
  34. 3(a)1 mark· Chemistry · Unit 1 Q3 3(a)Define the term 'enthalpy change of solution'.
  35. 3(a)1 mark· Chemistry · Unit 1 Q3 3(a)Hypothesis
  36. 3(b)1 mark· Chemistry · Unit 1 Q3 3(b)Aim
  37. 3(b)(i)1 mark· Chemistry · Unit 1 Q3 3(b)(i)State Hess' Law.
  38. 3(b)(ii)5 marks· Chemistry · Unit 1 Q3 3(b)(ii)Use the data in Table 2 and apply Hess' Law to determine the enthalpy of solution of hydrogen fluoride gas.
  39. 3(b)(iii)3 marks· Chemistry · Unit 1 Q3 3(b)(iii)Any chemical change involves processes of bond making and bond breaking. Classify EACH process as exothermic or endothermic and, hence, explain the value obtained in (b)(ii) on page 5.
  40. 3(d)3 marks· Chemistry · Unit 1 Q3 3(d)Experimental method
  41. 3(e)(i)3 marks· Chemistry · Unit 1 Q3 3(e)(i)Variables: Manipulated
  42. 3(e)(ii)1 mark· Chemistry · Unit 1 Q3 3(e)(ii)Variables: Responding
  43. 3(e)(iii)1 mark· Chemistry · Unit 1 Q3 3(e)(iii)Variables: Controlled
  44. 3(f)1 mark· Chemistry · Unit 1 Q3 3(f)Expected results
  45. 3(g)1 mark· Chemistry · Unit 1 Q3 3(g)Treatment of results
  46. 3(h)1 mark· Chemistry · Unit 1 Q3 3(h)ONE source of error in the experiment
  47. 4(a)2 marks· Chemistry · Unit 1 Q4 4(a)Define the term 'standard enthalpy of formation'.
  48. 4(a)1 mark· Chemistry · Unit 1 Q4 4(a)State Hess's Law.
  49. 4(b)1 mark· Chemistry · Unit 1 Q4 4(b)Write a balanced equation for formation of CaO(s).
  50. 4(b)(i)2 marks· Chemistry · Unit 1 Q4 4(b)(i)Define standard enthalpy change of formation.
  51. 4(b)(ii)2 marks· Chemistry · Unit 1 Q4 4(b)(ii)Define lattice energy.
  52. 4(c)6 marks· Chemistry · Unit 1 Q4 4(c)Construct a Born-Haber cycle for the formation of CaO(s) showing clearly, using equations, the steps of the enthalpy changes involved.
  53. 4(c)(i)2 marks· Chemistry · Unit 1 Q4 4(c)(i)State Hess's Law.
  54. 4(c)(i)6 marks· Chemistry · Unit 1 Q4 4(c)(i)Which enthalpy values correspond to EACH of the stages I, III and IV in the cycle above?
  55. 4(c)(ii)6 marks· Chemistry · Unit 1 Q4 4(c)(ii)Construct a diagram of a well-labelled Born-Haber cycle showing the formation of magnesium oxide (MgO) from magnesium metal and oxygen gas. On your diagram, show clearly ALL the enthalpy changes and species involved in…
  56. 4(c)(ii)6 marks· Chemistry · Unit 1 Q4 4(c)(ii)Calculate the lattice energy of MX(s).
  57. 4(d)4 marks· Chemistry · Unit 1 Q4 4(d)Distinguish between 'exothermic enthalpy change' and 'endothermic enthalpy change', citing enthalpy changes from your Born-Haber cycle in (c) to support your answer.
  58. 4(d)4 marks· Chemistry · Unit 1 Q4 4(d)Account for the difference in the lattice energy for MgCl₂(s) and NaCl(s).
  59. 4(e)2 marks· Chemistry · Unit 1 Q4 4(e)Explain, by writing an equation, how the data from the Born-Haber cycle can be used to calculate the lattice energy of CaO(s).
  60. 4(e)2 marks· Chemistry · Unit 1 Q4 4(e)Explain why the molar enthalpy changes for the following reactions have identical values: HCl (aq) + NaOH (aq) → NaCl (aq) + H₂O(l); H₂SO₄ (aq) + 2KOH (aq) → K₂SO₄ (aq) + 2H₂O(l).
  61. 8(a)(i)2 marks· Chemistry · Unit 1 Q8 8(a)(i)Calculate the mean of ΔHsoln NaCl from the data.
  62. 8(a)(ii)3 marks· Chemistry · Unit 1 Q8 8(a)(ii)Comment on the precision and accuracy of the results.
  63. 8(a)(iii)3 marks· Chemistry · Unit 1 Q8 8(a)(iii)Calculate the standard deviation of the data and explain the significance of the value.
  64. 8(b)(i)6 marks· Chemistry · Unit 1 Q8 8(b)(i)Discuss whether each instrument is appropriate for the measurement taken and suggest possible alternatives where necessary.
  65. 8(b)(ii)4 marks· Chemistry · Unit 1 Q8 8(b)(ii)Give TWO reasons for calibrating an instrument such as a thermometer and suggest TWO steps involved.
  66. 9(d)1 mark· Chemistry · Unit 1 Q9 9(d)The carbonyl group, >C=O, has absorption peaks in the region of 1680 to 1750 cm⁻¹, while the peaks for the alkene group, >C=C<, are manifested in the region of 1610 to 1680 cm⁻¹. What does this say about the bond…
  67. 121 mark· Chemistry · Unit 1 Q12 12What is the activation energy of the REVERSE reaction?
  68. 131 mark· Chemistry · Unit 1 Q13 13What type of heat change occurs at O?

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