How does a chemical equation express relationship between substance?

In a chemical equation, the reactants are written on the left, and the products are written on the right. The coefficients next to the symbols of entities indicate the number of moles of a substance produced or used in the chemical reaction. The reactants and products are separated by an arrow, usually read aloud as "yields."Chemical equations should contain information about the state properties of products and reactants, whether aqueous (dissolved in water) solid (s), liquid (l), or gas (g).