what is activation energy

Activation energy is the minimum amount of energy required for a chemical reaction to occur. It is the energy needed to activate atoms or molecules to a state in which they can undergo a chemical transformation or physical transport. In the Arrhenius model of reaction rates, activation energy is measured in kilojoules per mole or kilocalories per mole. The activation energy can be thought of as the magnitude of the potential barrier separating the initial and final thermodynamic state. For a chemical reaction to proceed at a reasonable rate, the temperature of the system should be high enough such that there exists an appreciable number of molecules with translational energy equal to or greater than the activation energy. The source of activation energy is typically heat, with reactant molecules absorbing thermal energy from their surroundings. This thermal energy speeds up the motion of the reactant molecules, increasing the frequency and force of their collisions, and also jostles the atoms and bonds within the individual molecules, making it more likely that bonds will break. The process of speeding up a reaction by reducing its activation energy is known as catalysis, and the factor thats added to lower the activation energy is called a catalyst. Biological catalysts are known as enzymes. Activation energy is denoted by Ea and is usually measured in joules or kilojoules per mole or kilocalories per mole. The activation energy formula is K = Ae^(-Ea/RT), where K is the rate constant, A is the Arrhenius constant, Ea is the activation energy, R is the gas constant, and T is the temperature. Activation energy is a fundamental concept in chemical kinetics and is crucial for understanding the rates of chemical reactions.