Enthalpy: Exothermic and Endothermic reactions.
Spontaneous reactions do occur, as chemists would call it. Spontaneous is a change that, once begun, will indeed continues with no need for the input of energy. Thermodynamic is the study of how heat and other forms of energy are involved in chemical and physical reaction. A second theory is now processed called kinetics which is judgmental on the rate of reactions. Kinetics are the study of reaction rates and how they can be affected by variables such as concentration, particle, size, and temperature.
Heat energy changes: Endothermic and Exothermic reactions.
Enthalpy change; The change in heat energy for a process that occurs at constant pressure; symbolized by ^H.
Energy diagram is a graph showing how energy changes during the course of a reaction. Activation energy is the energy that must be gained by molecules so they can break existing bonds and undergo a reaction. The outer,edoate state that is a combination of reactant and product atoms.
Catalyst: a substance that provides a lower energy pathway for a reaction which increases the speed of a reaction; it is not consumed (used up) during the reaction.