Chemical reactions and energy

All reactions release or absorb energy

This energy can take many forms (heat, light, sound, etc.)

energy is absorbed when bonds break

energy is released when bonds form

Chemical reactions that release energy are called exergonic reactions

The activation energy required to break the original bonds is less than the energy released when the new bonds form

If the primary energy release is thermal energy, we call the reaction an exothermic reaction

These reactions provide most of the power used in homes and industry

Reactions that require more energy to break the original bonds than what is released when the new bonds form are called endergonic reactions

Electricity is often used to provide the energy necessary for the reaction to occur

If the energy needed to keep a reaction going is in the form of thermal energy we call the reaction an endothermic reaction

Remember that energy cannot be created or destroyed only transformed

In chemical reactions the energy of the reactants has to be equal to the energy of the products plus any energy released