what are reactants and products
ReactantsâProducts. In a chemical reaction, substances (elements and/or compounds) called reactants are changed into other substances (compounds and/or elements) called products.hey indicate the number of each chemical species that reacts or is formed. Methane and oxygen (oxygen is a diatomic â two-atom â element) are the reactants, while carbon dioxide and water are the products. All the reactants and products are gases (indicated by the gâs in parentheses).