Factors affecting equilibrium and KEdexcel International A Level Chemistry: Mind map

Exam questions on Factors affecting equilibrium and K

1. Ammonia is manufactured by the Haber process: N₂(g) + 3H₂(g) ⇌ 2NH₃(g), ΔH = −92 kJ mol⁻¹. The reaction is carried out at about 450 °C and 200 atm using an iron catalyst.
   Explain why using the iron catalyst does not change the equilibrium yield of ammonia.2 marks
2. Limestone is heated in a sealed kiln in which this equilibrium is established: CaCO₃(s) ⇌ CaO(s) + CO₂(g), ΔH = +178 kJ mol⁻¹. For this equilibrium Kp = p(CO₂).
   The volume of the sealed kiln is halved at constant temperature. Explain why the equilibrium pressure of carbon dioxide returns to its original value.2 marks
3. The Contact process makes sulfur trioxide: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g), ΔH = −196 kJ mol⁻¹. The entropy change of the system is −188 J K⁻¹ mol⁻¹, and both this and ΔH may be assumed constant with temperature. Use R = 8.31 J K⁻¹ mol⁻¹.
   Calculate ΔStotal at 700 K and hence the value of K at 700 K.3 marks