-Energy

= = =__**Energy**__=

media type="youtube" key="x4CTceusK9I" height="315" width="560" Energy happens in chemistry whenever there is a change to either the atomic, molecular, or aggregate structures, because with such a change comes a decrease or increase of energy. Sometimes energy is transferred to the surroundings and the reactants in either heat or light. If a reaction is exergonic then it has less energy at the end then when it begin, but if it is endergonic then it has more energy at the end then it did in the beginning. If a reaction is exothermic then it releases heat to its surroundings but if it is endothermic then it absorbs heat. Chemical reactions don't happen unless the reactants have an energy barrier, the activation energy. The activation energy for a chemical reaction can be heat, light, electricity, or mechanical force. Free energy is also useful to determine if the chemical reaction is possible and to determine the state of equilibrium of the chemical reaction. A reaction is possible only is the total change in the Gibbs free energy formula is negative but if the change is zero then the reaction is at equilibrium. The only forms of energy for electrons are atoms and molecules. Also the phase of the of a substance can also be determined by its energy and the energy of its surroundings. Chemical energy is used to find the potential of a chemical substance to have a chemical reaction or to transform other chemical substances. Energy is also useful for chemistry because chemists are always trying to find new sources of energy such as energy or wind energy to make people less dependent on oil.