Activation energy

Definition

Activation energy is the minimum amount of energy required to start a chemical reaction. It determines the rate at which a reaction proceeds.

5 Must Know Facts For Your Next Test

1. Activation energy is often denoted by Ea in equations.
2. Enzymes lower the activation energy needed for biochemical reactions, increasing reaction rates.
3. Activation energy can be provided in various forms such as thermal energy (heat).
4. In a potential energy diagram, activation energy is represented as the peak between reactants and products.
5. Catalysts do not alter the overall change in free energy (ΔG) but rather decrease the activation energy.

Review Questions

• What role do enzymes play in relation to activation energy?
• How does activation energy affect the rate of a chemical reaction?
• In what way does a catalyst influence activation energy?

Related terms

Potential Energy:

Energy stored within a system due to its position or arrangement.

Kinetic Energy: Energy that an object possesses due to its motion.

Free Energy: The amount of work that can be performed by a system at constant temperature and pressure.