This question is about chemical equilibria in industrial and metallurgical processes.
Methanol is manufactured industrially by the catalytic hydration of carbon monoxide. The equilibrium is shown below:
CO(g)+2H2(g)⇌CH3OH(g)ΔH=−91 kJ mol−1Equilibrium 20.1 \text{CO}(\text{g}) + 2\text{H}_2(\text{g}) \rightleftharpoons \text{CH}_3\text{OH}(\text{g}) \quad \Delta H = -91\text{ kJ mol}^{-1} \quad \text{Equilibrium 20.1} CO(g)+2H2(g)⇌CH3OH(g)ΔH=−91 kJ mol−1Equilibrium 20.13.00 mol CO(g)3.00\text{ mol }\text{CO}(\text{g})3.00 mol CO(g) is mixed with 5.00 mol H2(g)5.00\text{ mol }\text{H}_2(\text{g})5.00 mol H2(g) in a 4.00 dm34.00\text{ dm}^34.00 dm3 container. The mixture is heated to 250 ∘C250\text{ }^\circ\text{C}250 ∘C with a copper-zinc oxide catalyst and allowed to reach equilibrium. The equilibrium mixture contains 1.50 mol CH3OH1.50\text{ mol }\text{CH}_3\text{OH}1.50 mol CH3OH.
Determine the equilibrium constant KcK_{\text{c}}Kc for Equilibrium 20.1 (including units), and explain why the operational conditions (temperature and pressure) used by industry are a compromise compared to those that would give the maximum equilibrium yield of methanol.
In metallurgy, hydrogen gas can be used to reduce iron oxides at high temperature, as shown in Equilibrium 20.2.
Fe3O4(s)+4H2(g)⇌3Fe(s)+4H2O(g)Equilibrium 20.2 \text{Fe}_3\text{O}_4(\text{s}) + 4\text{H}_2(\text{g}) \rightleftharpoons 3\text{Fe}(\text{s}) + 4\text{H}_2\text{O}(\text{g}) \quad \text{Equilibrium 20.2} Fe3O4(s)+4H2(g)⇌3Fe(s)+4H2O(g)Equilibrium 20.2When the temperature is increased, the value of Kp⇌K_{\text{p}}\rightleftharpoonsKp⇌ increases. Determine whether the forward reaction is exothermic or endothermic. Explain your answer.
Two students are discussing the effect of pressure on the equilibrium position of Equilibrium 20.2.
Student 1 says: "There are more total moles of products than reactants, so increasing the pressure will shift the equilibrium to the left-hand side."
Student 2 disagrees.
Determine which student is correct. Justify your answer.
