The position of equilibrium
3 marks · EasyA reversible reaction is shown below and is carried out in a sealed container: The forward reaction is endothermic.
State what will happen to the position of equilibrium if the temperature is increased.
State what happens to the amount of if the pressure is decreased.
Give a reason for your answer to part (b).
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.
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(a) The position of equilibrium shifts to the right (towards products).
(b) The amount of A increases.
(c) Equilibrium shifts to the side with more moles of gas (right), since pressure is decreased, so more B is formed and A is used up less.
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Marking points
B1 (a) · 1 mark · Position of equilibrium shifts to the right (towards more B/products).
B2 (b) · 1 mark · States the amount of A increases (or less A is converted). (follow-through)
B3 (c) · 1 mark · Explains increase using moles of gas: decrease in pressure favours side with more gas (the right/products/2B). (follow-through)
Worked solution
a) Increasing the temperature favours the endothermic direction, so the position of equilibrium shifts to the right (towards making more B).
b) Decreasing pressure increases the amount of A.
c) This is because the equilibrium shifts to the side with more moles of gas (right), so more B is formed and more A remains.