Paper 2 - Reversible reactions and equilibria

Question 1

What can a reversible reaction do in a sealed container?

Answer 1

A reversible reaction can reach dynamic equilibrium

Question 2

What are the characteristics of a reaction at dynamic equilibrium?

Answer 2

• the forward and reverse reactions occur at the same rate
• the concentrations of reactants and products remain constant

Question 3

Why does a catalyst not affect the position of equilibrium in a reversible reaction?

Answer 3

A catalyst speeds up the rate of the forward reaction and the backward reaction by the same amount

Question 4

What is the effect of changing temperature on the position of equilibrium in a reversible reaction?

Answer 4

• The equilibrium moves to oppose the change
• If the temperature is increased, equilibrium moves to endothermic side. E.g. if this is the products side, more products will be formed

Question 5

What is the effect of changing pressure on the position of equilibrium in a reversible reaction?

Answer 5

• The equilibrium moves to oppose the change
• If pressure is increased, the equilibrium moves to the side with less gas molecules. If this is the right side - more products are formed

Question 6

What happens to the yield if the temperature is increased in an exothermic reaction?

Answer 6

decreases yield of reaction

Question 7

What happens to the yield if the temperature is increased in an endothermic reaction?

Answer 7

increases yield of reaction

Question 8

What happens to the yield if the temperature is decreased in an exothermic reaction?

Answer 8

increases yield of reaction

Question 9

What happens to the yield if the temperature is decreased in an endothermic reaction?

Answer 9

decreases yield of reaction