Chapter 5: Unit 10. Energy Diagram

Energy Diagram

A potential energy diagram illustrates the energy changes that occurs during a chemical reaction. Energy is plotted along vertical axis and reaction coordinate is plotted along horizontal axis. According to collision theory, reactant molecules collide during chemical reaction. Molecules with proper kinetic energy called activation energy and alignment successfully form the product. For every reaction there is a certain amount of activation energy required to form the product, During the chemical reaction some old bonds are broken and new bonds are formed. When the reactant reaches the intermediate stage during reaction with proper activation energy, the species is called Activated complex or transition state. The transition state is located at the top of the energy barrier that separates reactants from products on the potential energy diagram. Also, the reaction can release the heat or absorb the heat during the chemical reaction. This quantity of heat is called heat of the reaction or enthalpy(∆H). When the reaction is releasing heat, product enegy level is below reactant energy level, since the total energy in a chemical reaction is always conserved.