Methanol (CH3OH\text{CH}_3\text{OH}CH3OH) is manufactured on an industrial scale by reacting carbon monoxide (CO\text{CO}CO) with hydrogen (H2\text{H}_2H2) at a temperature of 250∘C250^\circ\text{C}250∘C and a pressure of 80 atm80\text{ atm}80 atm. Under these conditions, the percentage yield of methanol at equilibrium is approximately 20%20\%20%.
The chemical equation representing this industrial process is:
CO(g)+2H2(g)⇌CH3OH(g)ΔH=−91 kJ/mol \text{CO(g)} + 2\text{H}_2\text{(g)} \rightleftharpoons \text{CH}_3\text{OH(g)} \quad \Delta H = -91\text{ kJ/mol} CO(g)+2H2(g)⇌CH3OH(g)ΔH=−91 kJ/molState what the symbols ⇌\rightleftharpoons⇌ and ΔH\Delta HΔH represent.
Name the metal catalyst commonly used in this industrial synthesis of methanol.
Predict the effect on the equilibrium yield of methanol if the reaction is carried out at a temperature lower than 250∘C250^\circ\text{C}250∘C, but at the same pressure of 80 atm80\text{ atm}80 atm. [Assume the reaction reaches equilibrium] Give a reason for your answer.
Predict the effect on the equilibrium yield of methanol if the reaction is carried out at a pressure lower than 80 atm80\text{ atm}80 atm, but at the same temperature of 250∘C250^\circ\text{C}250∘C. [Assume the reaction reaches equilibrium] Give a reason for your answer.
One method of obtaining carbon monoxide is by the steam reforming of methane from natural gas. Carbon monoxide can also be produced by the thermal decomposition of calcium carbonate. The equation for this decomposition is:
CaCO3(s)→heatCaO(s)+CO2(g) \text{CaCO}_3\text{(s)} \xrightarrow{\text{heat}} \text{CaO(s)} + \text{CO}_2\text{(g)} CaCO3(s)heatCaO(s)+CO2(g)State the type of reaction taking place when calcium carbonate is heated.
Suggest why it may be necessary or environmentally advantageous in the future to produce synthesis gas components (such as carbon monoxide and hydrogen) from renewable biomass gasification rather than from steam reforming of natural gas.
28 exam-style questions on Edexcel IGCSE Chemistry Reversible reactions and equilibria. Each one has a worked solution and a mark scheme showing where the marks go.