Adding a catalyst
3 marks · EasyA reversible reaction mixture is at equilibrium. A catalyst is added to the system.
Explain what happens to:
the rate at which the equilibrium is reached,
the position of equilibrium,
the amount of products at equilibrium.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a.i) The rate at which equilibrium is reached increases.
(a.ii) The position of equilibrium does not change.
(a.iii) The amount of products at equilibrium remains the same.
Common mistakes: Saying equilibrium position changes; Saying product amount increases
Show mark scheme and worked solution
Marking points
B1 (a(i)) · 1 mark · Correctly states that the rate at which equilibrium is reached increases.
B2 (a(ii)) · 1 mark · Correctly states that the position of equilibrium does not change.
B3 (a(iii)) · 1 mark · Correctly states that the amount of products at equilibrium stays the same.
Worked solution
i) The rate at which equilibrium is reached increases because the catalyst increases the speed of both the forward and backward reactions.
ii) The position of equilibrium does not change because the catalyst affects both reactions equally.
iii) Therefore, the amount of products at equilibrium remains unchanged.