Carbon monoxide can react with hydrogen to produce methanol in a homogeneous reversible reaction:
CO(g)+2H2(g)⇌CH3OH(g)ΔH∘=−90 kJ mol−1 \text{CO(g)} + 2\text{H}_2\text{(g)} \rightleftharpoons \text{CH}_3\text{OH(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 would show that this reaction mixture has reached equilibrium.
A 0.400 mol sample of carbon monoxide is mixed with hydrogen in a 1:2 1:2\,1:2 mole ratio and allowed to reach equilibrium in a sealed vessel at temperature TTT. At equilibrium, the mixture contains 0.250 mol of carbon monoxide. The total pressure of this mixture is 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 Kp K_p\,Kp 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.