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3 marksRates of Reaction

CSEC Chemistry · May/June 2008 · Paper 2 · Question 5(b)

Nitrogen, making up 78% of the atmosphere, is a stable diatomic molecule. It undergoes fixation reactions to produce nitrogenous compounds essential for plants. The Haber process, N₂(g) + 3H₂(g) ⇌ 2NH₃(g) with ΔH = -92 kJ mol⁻¹, uses pressures of 200-300 atmospheres and temperatures of 400-500°C.

Suggest reasons for using these reaction conditions. Explain your answer in terms of the equation above.

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Other parts of this question

  1. 5(a)(i)From the compounds A to D above, select ONE compound which is saturated and ONE compound which is unsaturated.[2 marks]
  2. 5(a)(ii)Name AND give the general formula for the homologous series to which EACH of the two compounds selected in (a) (i) above belongs.[4 marks]
  3. 5(c)(i)With reference to the nitrogen cycle: Name ONE process by which nitrogen in the atmosphere can be converted into nitrates.[1 mark]
  4. 5(c)(ii)With reference to the nitrogen cycle: Name ONE process by which nitrogen in the nitrates in soil is released back into the atmosphere.[1 mark]
  5. 5(d)(i)Which of these two metal nitrates, P or Q, possibly contains Group I metal? Group 2 metal?[2 marks]
  6. 5(d)(ii)Write a chemical equation to show the reaction taking place when Q is heated.[2 marks]

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