An industrial chemist investigates reactions related to the synthesis of alternative fuels and fuel intermediates.
The table shows three possible reversible reactions that could be used. The enthalpy changes are also shown.
| Reaction | Equation | ΔH\Delta HΔH in kJ/mol |
|---|---|---|
| 1 | CO(g)+2H2(g)⇌CH3OH(g)\text{CO}(\text{g}) + 2\text{H}_2(\text{g}) \rightleftharpoons \text{CH}_3\text{OH}(\text{g})CO(g)+2H2(g)⇌CH3OH(g) | −91-91−91 |
| 2 | CH3OH(g)+HCl(g)⇌CH3Cl(g)+H2O(g)\text{CH}_3\text{OH}(\text{g}) + \text{HCl}(\text{g}) \rightleftharpoons \text{CH}_3\text{Cl}(\text{g}) + \text{H}_2\text{O}(\text{g})CH3OH(g)+HCl(g)⇌CH3Cl(g)+H2O(g) | +18+18+18 |
| 3 | 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)⇌CH3OH(g)+H2O(g) | −49-49−49 |
(i) For reaction 1, predict whether the pressure should be low or high to give the greatest yield of products.
(ii) Give a reason for your choice.
(i) For reaction 1, predict whether the temperature should be low or high to give the greatest yield of products.
(ii) Give a reason for your choice.
For reaction 2, suggest why changing the temperature will have less effect on the yield of products than in reactions 1 and 3.
(i) For reaction 3, predict the effect on the rate of the forward reaction of increasing the pressure, without changing the temperature.
(ii) Explain your prediction in terms of the particle collision theory.
The manufacturer makes a batch of propyl ethanoate from propan-1-ol and ethanoic acid using this reaction:
C3H7OH+CH3COOH→CH3COOC3H7+H2O \text{C}_3\text{H}_7\text{OH} + \text{CH}_3\text{COOH} \rightarrow \text{CH}_3\text{COOC}_3\text{H}_7 + \text{H}_2\text{O} C3H7OH+CH3COOH→CH3COOC3H7+H2OHe starts with 180 kg180 \text{ kg}180 kg of propan-1-ol. Calculate the maximum mass of propyl ethanoate he could obtain.
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.