Final answer:
The activation energy is the minimum energy required for a reaction to occur when two molecules collide.
Step-by-step explanation:
The minimum energy required before two molecules can be successful in producing a reaction is called the activation energy. It is the energy threshold that the particles in a reaction must have to react when they collide. Activation energy is the minimum amount of energy needed for a reaction to occur, and it is usually expressed as the energy necessary to form one mole of activated complex.