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3 marksEnergetics

CAPE Chemistry Unit 1 · May/June 2023 · Paper 2 · Question 1(d)(iii)

Hess' law and Born-Haber cycle for lead(II) fluoride.

Using the data in Table 1, calculate the lattice energy of PbF₂(s).

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Other parts of this question

  1. 1(a)(i)State Boyle's law.[1 mark]
  2. 1(a)(ii)State Charles' law.[1 mark]
  3. 1(b)List FOUR assumptions made about gas molecules in the kinetic molecular theory with reference to ideal gases.[4 marks]
  4. 1(c)A flask has a mass of 47.392 g when empty, and 47.816 g when filled with acetone vapor at 100 °C and 745 mm Hg. If the volume of the flask is 247.3 mL,…[4 marks]
  5. 1(d)(i)State Hess' law.[2 marks]
  6. 1(d)(ii)Construct a Born–Haber cycle for the formation of lead (II) fluoride, PbF₂(s), showing clearly, using equations, the steps of the enthalpy changes involved.[6 marks]
  7. 1(e)(i)State the effect of ionic charge on the magnitude of the lattice energy.[1 mark]
  8. 1(e)(ii)State the effect of ionic radius on the magnitude of the lattice energy.[1 mark]
  9. 1(f)(i)Write the simplest ionic equation for the formation of the yellow precipitate when silver nitrate solution acidified with dilute nitric acid is added to an…[2 marks]
  10. 1(f)(ii)State the result observed when concentrated ammonia solution is added to this yellow precipitate.[1 mark]
  11. 1(f)(iii)State why the silver nitrate solution is acidified when testing for iodide ions.[1 mark]
  12. 1(f)(iv)Explain why dilute hydrochloric acid is not used to acidify the silver nitrate solution in this test for iodide ions.[1 mark]
  13. 1(g)Describe the result observed when chlorine water is added to a solution of potassium bromide, followed by aqueous silver nitrate.[2 marks]

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