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5.2 Reversible reactions and equilibria

5.2 Reversible reactions and equilibria

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Question 2

Methanol, a key chemical feedstock and potential renewable fuel, can be synthesised by the hydrogenation of carbon dioxide:

CO2(g)+3H2(g)⇌CH3OH(g)+H2O(g) \text{CO}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons \text{CH}_3\text{OH}(\text{g}) + \text{H}_2\text{O}(\text{g}) CO2​(g)+3H2​(g)⇌CH3​OH(g)+H2​O(g)

In this reaction, the forward reaction is exothermic.

The industrial conditions typically used are:

  • a copper-zinc-alumina catalyst
  • a temperature of 250∘C250^\circ\text{C}250∘C

Explain, in terms of their effects on the rate of attainment of equilibrium and the equilibrium yield of methanol, why this reaction is carried out using a catalyst at 250∘C250^\circ\text{C}250∘C rather than without a catalyst at a higher temperature.

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Markscheme

5.2 Reversible reactions and equilibria Questions

  1. GCSE
  2. /Chemistry
  3. /5.2 Reversible reactions and equilibria

38 exam-style questions on Edexcel GCSE Chemistry 5.2 Reversible reactions and equilibria, covering 5.2.1 Reversible reactions and dynamic equilibrium, 5.2.2 The Haber process, and 5.2.3 Changing the position of a dynamic equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.

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