A Level Biology Practice Exam

What is the term for the energy required to initiate a reaction?

1. Activation energy

2. Potential energy

3. Kinetic energy

4. Free energy

The correct answer is: Activation energy

The correct term for the energy required to initiate a reaction is activation energy. This is the minimum amount of energy that reactants must possess for a chemical reaction to occur. Activation energy is crucial because it is the energy barrier that separates reactants from products; it needs to be overcome for the reaction to proceed. In terms of other options, potential energy relates to stored energy in an object due to its position, kinetic energy refers to the energy of motion, and free energy is a thermodynamic quantity that indicates the amount of work a system can perform at constant temperature and pressure, but none of these terms specifically describe the energy needed to start a reaction.