Final answer:
When a reaction reaches a state where the forward and reverse reactions occur at the same rate, it is in a state of dynamic equilibrium. This state is characterized by constant, unchanging concentrations of reactants and products, despite ongoing reaction processes.
Step-by-step explanation:
The state that has been reached when both directions of a reaction occur with the same frequency is called equilibrium, or more specifically, dynamic equilibrium. At this point, though the concentrations of the reactants and products remain constant, chemical reactions continue to occur in both the forward and reverse directions. An example of a reaction in dynamic equilibrium could be written as: A + B ⇌ C + D, using the double-headed arrow to denote that the reaction is at equilibrium.
Chemical equilibrium is characterized by several features:
- The rate of the forward reaction is equal to the rate of the reverse reaction.
- There are no observable changes in the concentrations of reactants and products, even though the reaction is ongoing.
- Equilibrium does not mean the concentrations of reactants are equal to the concentrations of products, but that the amounts of reactants and products remain unchanged over time.
Understanding that reactions at equilibrium have reached a balance in reaction rates is fundamental to many chemical processes and principles, though the balance does not imply that reactants and products are present in equal proportions, just that their concentrations do not vary.