Product

It applies to the total mass of every reactant and every product involved in the reaction. The products can have very different properties from the reactants, but they contain the same collection of atoms.

The products are the new substances formed, so they go on the right. Read the arrow as “produces”, “forms” or “reacts to make”; it shows the direction of the change and is not an equals sign.

Existing combinations change and new combinations form, producing product particles with different chemical identities.

Consequently, every atom present among the reactants must also be present among the products. This is the particle-level explanation of the conservation of mass: the total mass of the products equals the total mass of the reactants for the complete reaction system.