A-Level Reversible reactions and the position of equilibrium: worked solution

Question

Consider the steam-reforming equilibrium CH4 (g) + H2O (g) ⇌ CO (g) + 3H2 (g). Predict how the position of equilibrium is affected in each of the following situations. The reactor volume is doubled: The nickel catalyst is supplied as a powder rather than as granules:

Reactor volume doubled: pressure falls, so equilibrium shifts to the side with more moles of gas. Left side has 2 mol gas (CH4 + H2O), right side has 4 mol gas (CO + 3H2), so equilibrium shifts to the right (towards products). Catalyst as powder rather than granules: a catalyst does not change the position of equilibrium (it speeds up forward and reverse rates equally). The larger surface area only lets equilibrium be reached faster - no change in position.