Explain why energy is necessary to chemical reactions, and describe some common sources of energy.

The energy required to begin a reaction is known as activation energy. The most common form of activation energy is going to be heat. For example: combustible materials will begin reacting with oxygen (burning) when they are heated enough. Typically, if another form of energy is used, it will ultimately be turned into thermal energy. For instance, the kinetic energy found in an internal combustion engine can compress a cylinder full of air, which will cause the diesel fuel that is sprayed into the cylinder to combust. Although it was kinetic energy that was used, the end result was that the temperature of the gas increased, which caused the combustion to occur.