This question is about equilibria involving sulfur and iron compounds.
Sulfur trioxide is manufactured industrially by the Contact Process. The equilibrium is shown below:
2SO2(g)+O2(g)⇌2SO3(g)ΔH=−197 kJ mol−1Equilibrium 20.1 2\text{SO}_2(\text{g}) + \text{O}_2(\text{g}) \rightleftharpoons 2\text{SO}_3(\text{g}) \quad \Delta H = -197\text{ kJ mol}^{-1} \quad \text{Equilibrium 20.1} 2SO2(g)+O2(g)⇌2SO3(g)ΔH=−197 kJ mol−1Equilibrium 20.12.00 mol SO2(g)2.00\text{ mol }\text{SO}_2(\text{g})2.00 mol SO2(g) is mixed with 1.00 mol O2(g)1.00\text{ mol }\text{O}_2(\text{g})1.00 mol O2(g) in a 5.00 dm35.00\text{ dm}^35.00 dm3 container. The mixture is heated to 450 ∘C450\text{ }^\circ\text{C}450 ∘C with a vanadium(V) oxide catalyst and allowed to reach equilibrium. The equilibrium mixture contains 0.50 mol SO30.50\text{ mol }\text{SO}_30.50 mol SO3.
Determine the equilibrium constant KcK_{\text{c}}Kc for Equilibrium 20.1 (including units), and explain why the operational conditions used by industry may be different from those required for a maximum equilibrium yield of sulfur trioxide.
In industry, carbon monoxide is also used to reduce iron(III) oxide as shown in Equilibrium 20.2. The reaction is carried out at high temperature.
Fe2O3(s)+3CO(g)⇌2Fe(s)+3CO2(g)Equilibrium 20.2 \text{Fe}_2\text{O}_3(\text{s}) + 3\text{CO}(\text{g}) \rightleftharpoons 2\text{Fe}(\text{s}) + 3\text{CO}_2(\text{g}) \quad \text{Equilibrium 20.2} Fe2O3(s)+3CO(g)⇌2Fe(s)+3CO2(g)Equilibrium 20.2When the temperature is increased, the value of Kp⇌K_{\text{p}}\rightleftharpoonsKp⇌ decreases. 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.
