An chemical reaction describes how atoms, the primary elements of matter, alter their arrangement to form new configurations. The substances that react with one and are called reactionants. In the right conditions like temperatures and time or pressure the chemical bonds of the reactants break down and the atoms make new bonds, which result in different combinations. The compounds created by this recombination process are known as the products from the process. If chemical reactions are documented in a journal, the reactants are written on the left, like an equation in math which is one reaction and another. A arrow is written just to the right of the reactants to signal the moment when a reaction takes place and the product of the reaction is later written in the correct side.