Activation energy is a fundamental concept in chemistry and chemical kinetics that plays a crucial role in understanding chemical reactions. This concept allows us to understand why some reactions occur quickly while others are much slower. What is activation energy ? Activation energy (Ea) is the minimum amount of energy that must be provided to reactant molecules or particles so that they can react and become chemicals. In other words, it represents the energy barrier that must be overcome ... Learn what activation energy is, how it affects chemical reactions, and how to calculate it using the Arrhenius equation. Find examples, graphs, and FAQs on activation energy and its factors. Activation energy is the minimum energy barrier that reactant molecules must overcome to transform into products . A reaction occurs only if enough molecules have kinetic energy equal to or greater than this barrier, which usually requires sufficiently high temperature.