Equilibrium (College Board AP® Chemistry)

Exam Questions

3 mins3 questions
11 mark

Which statement below best describes a dynamic equilibrium?

  • The rate of the forward reaction is equal to the reverse reaction, and the concentrations of reactants and products is constant

  • The rate of the forward reaction is equal to the reverse reaction in a closed system, and the concentrations of the reactants and products are equal

  • The rate of the forward reaction is equal to the reverse reaction in a closed system, and the concentrations of the reactants and products is constant

  • The rate of reaction changes in either direction to counteract a change in conditions

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21 mark

When a chemical reaction reaches equilibrium which of the following can be said about the concentrations of the substances present, and the rates of reaction?

  • The concentrations of the reactants and products continue to change and the rates of forward and reverse reactions remain the same.

  • The concentrations of the reactants and products remains constant and the rates of forward and reverse reactions remain the same.

  • The concentrations of the reactants and products continue to change and the rates of forward and reverse reactions are different.

  • The concentrations of the reactants and products remain constant and the rates of forward and reverse reactions are different.

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31 mark
Sample rate versus time graph for a reversible reaction

The graph above shows how rate changes with time for a reversible reaction.

Which of the following is not correct about point A?

  • The rate of the forward and reverse reaction reactions remain constant.

  • Partial pressures remain constant

  • The number of particles of each species remains constant

  • The concentrations of reactants and products are equal

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