All around us, but also inside our own bodies, numerous chemical transformations are in operation, A chemical reaction (chemical transformation) is characterized by an initial state, made up of reactants, and a final  state composed of products.

In the course of a reaction, matter is conserved. That is, an element  may appear in different forms at the beginning and at the end of a reaction, but in no case is ever lost.

The chemical equation enables us to indicate the proportions of reactants and products put into play. These proportions are referred to as the stoichiometric coefficients.

Fix the number of molecules using the sliding cursors, then click on [play] to initiate the reaction.