When a reaction system is at equilibrium: a. there is no more chemistry happening. b. the amounts of reactants and products are exactly equal. c. the reaction rate in the forward direction is at a maximum. d. the reaction rate in the reverse direction is at a minimum. e. the rates of the reaction in the forward and reverse directions are exactly equal.

Option (e) is the correct answer.

Explanation:

Equilibrium is defined as the state of a chemical reaction in which the rate of forward reaction is equal to the rate of backward reaction.

The state of equilibrium is represented by a double sided arrow as "" in a chemical equation.

For example,

Therefore, we can conclude that when a reaction system is at equilibrium then the rates of the reaction in the forward and reverse directions are exactly equal.

Oxygen

Explanation:

Oxygen is 21% of the gases that make up our air