Why is energy required to start a reaction?

Why do all chemical reactions need energy to get started? In order for reactions to begin, reactant molecules must bump into each other, so they must be moving, and movement requires energy. When reactant molecules bump together, they may repel each other because of intermolecular forces pushing them apart.

What is required for a reaction to start?

Reactions require an input of energy to initiate the reaction; this is called the activation energy (EA). Activation energy is the amount of energy required to reach the transition state. The source of the activation energy needed to push reactions forward is typically heat energy from the surroundings.

Is the minimum energy required for a reaction to start?

The minimum amount of energy needed for a reaction to take place is called the activation energy .

What represents the activation energy?

symbol Ea