What does the term 'activation energy' describe?

The term 'activation energy' describes the minimum energy required for a chemical reaction to occur. This energy is essential because it allows reactants to reach an unstable transition state before forming products. It can be thought of as a barrier that must be overcome for the reaction to proceed.

When reactants collide, they must possess enough energy to break existing bonds and rearrange into new bonds. This is why the activation energy is a critical factor in determining the rate of a reaction; higher activation energies generally lead to slower reactions, as fewer reactant molecules will have sufficient energy to overcome this barrier at a given temperature.

Understanding activation energy is vital to comprehending reaction mechanisms, as catalysts are often used to lower this energy requirement, thereby increasing the reaction rate without being consumed in the process.