A chemical reaction is a process in which one or more substances, the reactants, are converted into one or more different substances, the products. Substances are chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. Chemical reactions are a very important part of technology and life itself. Burning fuel, making glass, making beer, or even making wine are just a few of the many examples of things that involve chemical reactions that have been known and used for thousands of years. Chemical reactions are also involved in the elements of the earth, the atmosphere, the oceans, and the wide range of complicated processes that take place in living systems. Chemical reactions are distinguished from physical changes. Physical changes include changes in state, such as the melting of ice in water or even the evaporation of water into air. If a physical change occurs, the physical properties of that substance will also change. But the chemical identity of the substance will remain the same. No matter what the chemical state, water (H2O) is the same compound, with each molecule made up of two hydrogen atoms and one atom made up of oxygen. During a chemical reaction, reactants interact when brought together. Sometimes other conditions are needed and sometimes the reaction will be spontaneous. During the reaction, the chemical binds to one or more reactants, changes and is reconfigured or combined with atoms or parts of other molecules of other reactants, and forms new chemicals. All the atoms of the reactants are preserved in the product... in the middle of the paper... a molecule is transferred by dissociation into one or more molecules. Reactions like these require more energy in the form of heat or light. “An example of this is cis-trans isomerization, where the cis form of a compound converts to the trans form or vice versa.” Chemical reactions don't just stop when ice turns to water. There are a handful of different types of chemical reactions to become familiar with. Not only does a chemical reaction exhibit physical signs of a change, but the formula of the reaction can also change. Bimolecular reactions occur when two molecules come together and react with each other. This is called chemical synthesis. This formula can go from A+BAB. Chemical reactions are everywhere, from frying an egg to producing a liter of Pepsi, there is much more happening within the process than just a physical change.