The effect of concentration
2 marks · EasyA system is at equilibrium with the following reaction:
At equilibrium, the concentration of Z is 4.0 mol/dm^3. If 2.0 mol/dm^3 of Z is suddenly removed, how many moles per dm^3 of Z will form to restore equilibrium? Assume all change is due to the forward reaction.
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2.0 mol/dm^3 (±0.1)
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Marking points
M1 · 1 mark · Recognises that 2.0 mol/dm^3 Z must be replaced to re-establish equilibrium.
A1 · 1 mark · Gives correct value of 2.0 mol/dm^3.
Worked solution
Original [Z] = 4.0 mol/dm^3. After removal, [Z] = 2.0 mol/dm^3.
To restore equilibrium, system must produce 2.0 mol/dm^3 of Z (the amount removed).