Question

At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction. Both the forward and the reverse reactions are occurring, but because they are occurring at the same rate, no change is observed in the appearance of the solution.

For this analysis, think about the affect that the addition or removal of reactant will have on the rate of the forward reaction relative to the rate of the reverse reaction at the instant that the reactant is added or removed. You also have to think about the addition or removal of product on the rate of the reverse reaction relative to the rate of the forward reaction.

a. When the concentration of reactant is increased for a system at equilibrium, what is the effect on the rate of the forward reaction? Does an increase in the rate of reactant have any effect on the rate of the reverse reaction? Explain your answer.

b. When the concentration of reactant is increased for a system at equilibrium, which reaction is immediately faster – the forward or the reverse reaction? Why?

c. As the reaction proceeds and the added reactant is used up, what happens to the rate of the forward reaction? At the point at equilibrium has been reached, what has happened to the rate of the forward reaction relative to the rate of the reverse reaction?

d. If reactant is removed from a system at equilibrium, what is the effect on the rate of the forward reaction? Does the rate of the reverse reaction change when reactant is removed?

e. When reactant is removed in a system at equilibrium, which reaction is faster – the forward reaction or the reverse reaction? Would that result in an accumulation of reactant or product in the flask?

f. Write a statement about why the addition of product causes the reaction to shift to reactants in terms of the relative rates of the forward and reverse reactions.

g. Write a statement from a kinetic perspective about why the removal of reactant causes the reaction to shift towards reactant.

Answer 1

a. When the concentration of reactant is increased for a system at equilibrium, what is the effect on the rate of the forward reaction? Answer = increases.

b. When the concentration of reactant is increased for a system at equilibrium, which reaction is immediately faster – the forward or the reverse reaction? Answer = forward reaction.

c. As the reaction proceeds and the added reactant is used up, what happens to the rate of the forward reaction?

answer = value is positive.

At the point at equilibrium has been reached, what has happened to the rate of the forward reaction relative to the rate of the reverse reaction?Answer = Higher

d. If reactant is removed from a system at equilibrium, what is the effect on the rate of the forward reaction? Answer = decreases.

Does the rate of the reverse reaction change when reactant is removed?Answer = changes and rate of reverse reaction decreases.

e. When reactant is removed in a system at equilibrium, which reaction is faster – the forward reaction or the reverse reaction? Answer = the reverse reaction.

Would that result in an accumulation of reactant or product in the flask?Answer = reactant.