Reversible Reactions and Equilibria
5 marks · EasyThis question is about dynamic equilibrium and how it is achieved in sealed containers.
Explain what is meant by dynamic equilibrium in a reversible reaction.
A chemical reaction is happening in a sealed container.
Describe what happens to the concentrations of reactants and products once dynamic equilibrium is reached.
State the essential feature of the rates of the forward and reverse reactions at equilibrium in a sealed container.
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) — · must show forward and reverse reactions continue, occur at same rate
(b(i)) — · must show concentrations remain constant
(b(ii)) — · must show forward and reverse reactions occur at equal rates
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Mentions that both the forward and reverse reactions are occurring
A1 (a) · 1 mark · States that the rates of the forward and reverse reactions are equal
B1 (b(i)) · 1 mark · States that the concentrations of reactants and products remain constant
M2 (b(ii)) · 1 mark · Mentions both forward and reverse reactions are ongoing at equilibrium
A2 (b(ii)) · 1 mark · States they occur at equal rates at equilibrium in a sealed container
Worked solution
a) Dynamic equilibrium is when, in a reversible reaction, both the forward and reverse reactions continue to happen but at the same rate, so there is no net change.
b(i) The concentrations of reactants and products remain constant at equilibrium.
b(ii) The essential feature is that the forward and reverse reactions occur at equal rates in a sealed container.