Carbon monoxide can react with hydrogen to produce methanol in a reversible homogeneous gas-phase reaction:
CO(g)+2H2(g)⇌CH3OH(g)ΔH∘=−90 kJ mol−1 \text{CO}(\text{g}) + 2\text{H}_2(\text{g}) \rightleftharpoons \text{CH}_3\text{OH}(\text{g}) \quad \Delta H^\circ = -90\text{ kJ mol}^{-1} CO(g)+2H2(g)⇌CH3OH(g)ΔH∘=−90 kJ mol−1State how a graph of partial pressure against time for this reaction mixture would show that the system has reached equilibrium.
A 0.500 mol0.500\text{ mol}0.500 mol sample of carbon monoxide is mixed with hydrogen in a 1:21:21:2 mole ratio and allowed to reach equilibrium in a sealed flask at temperature TTT. At equilibrium, the mixture contains 0.200 mol0.200\text{ mol}0.200 mol of carbon monoxide. The total pressure of this mixture is 1.80×104 kPa1.80 \times 10^4\text{ kPa}1.80×104 kPa.
Calculate the partial pressure, in kPa\text{kPa}kPa, of hydrogen in the equilibrium mixture.
Give an expression for the equilibrium constant (KpK_pKp) for this reaction and state its units.
Some more carbon monoxide is added to the equilibrium mixture. The new mixture is allowed to reach equilibrium at temperature TTT. State the effect, if any, on the partial pressure of methanol and on the value of KpK_pKp.
State the effect, if any, of the addition of a catalyst on the value of KpK_pKp for this equilibrium. Explain your answer.
31 exam-style questions on AQA A Level Chemistry Equilibrium constant $K_p$ for homogeneous systems (A-level only), covering Equilibrium constant $K_p$ for homogeneous systems (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.