Activation Energy

Swedish chemist Svante Arrhenius introduced the term in 1889, building on earlier work by Dutch chemist Jacobus Henricus van 't Hoff, who had noted in 1884 that equilibrium constants suggested a formula for reaction rates. Arrhenius formulated the concept to explain why most chemical reactions require added heat to proceed: reactant molecules must overcome an energy barrier to reach a transition state. His Arrhenius equation, published that same year, became fundamental to understanding how temperature affects reaction rates.