Key Concepts: Activation Energy

Core Definitions

• Activation Energy (Ea): The minimum energy required for a chemical reaction to begin.
• Energy Diagram: A graph showing energy changes during a reaction; Ea is the 'hill' reactants must overcome.
• Exothermic Reaction: Products have less energy than reactants; energy is released.
• Endothermic Reaction: Products have more energy than reactants; energy is absorbed.
• Activated Complex: The unstable, high-energy transition state at the top of the energy barrier.
• Catalyst: A substance that lowers activation energy without being consumed in the reaction.