What is the term for the minimum energy required for a substrate to undergo a chemical change?

The minimum energy required for a substrate to undergo a chemical change is termed activation energy. This is the energy barrier that must be overcome for reactants to transform into products during a chemical reaction. Activation energy is crucial in understanding reaction rates and the impact of catalysts, which lower this energy threshold, thereby increasing the rate of reaction without being consumed in the process.

Threshold energy typically refers to a level of energy that must be reached for a specific event to occur but is not the standard term used in the context of chemical reactions. Free energy is related to the energy available to do work in a system under constant temperature and pressure, while potential energy generally describes the stored energy in an object due to its position or state and is not specific to chemical transformations. Thus, activation energy is the most accurate term for what is being asked.