What happens in a chemical reaction?

As the chemical bonds are broken, the positions of electrons change, resulting in a product with properties that are different from the properties of the reactants. Various temperatures and catalysts are needed for different chemical reactions to occur. During a chemical reaction, new substances are produced as existing bonds are broken, atoms are rearranged, and new bonds are formed.

When two or more molecules interact and the molecules change. Bonds between atoms are broken down and created to form new molecules.