[Campbell Biology P.90] According to the text, which statement best characterizes a system ... | Practice Question

According to the text, which statement best characterizes a system at chemical equilibrium?

  • A: The concentrations of reactants and products are equal.
  • B: The forward reaction has completely stopped, and only the reverse reaction proceeds.
  • C: The forward and reverse reactions occur at the same rate, leading to stable concentrations of reactants and products.
  • D: All reactants have been converted to products, indicating the reaction has gone to completion.

Explanation

The text clearly defines chemical equilibrium: 'Eventually, the forward and reverse reactions occur at the same rate, and the relative concentrations of products and reactants stop changing. The point at which the reactions offset one another exactly is called chemical equilibrium. This is a dynamic equilibrium; reactions are still going on in both directions, but with no net effect on the concentrations of reactants and products.' Option C perfectly encapsulates this definition.