Chemical Equations:

The chemical equation is easily a representation of a chemical reaction within the chemist's shorthand. Within a chemical equation, the substances originally present are known as the reactants and the new substances being established are known as the products. In the chemical reaction, the reactants are on the left of the arrow and the products are on the right of the arrow. For instance, while looking at the mixture of hydrogen and oxygen into water, a water molecule would be the product on the right.

2H₂ + O₂ →   2H₂O

The hydrogen and oxygen would be the products and the water is the reactant if looking at the decomposition of water. The arrow means yields and is used to separate the reactants from the products.  It also denotes the direction of the reaction as described below.

2H₂O →    2H₂ + O₂

The single arrow in the above equation denotes in which the reaction will proceed in just one direction until it subsides or stops.  If the reaction is reversible, that is, it could proceed left to right and right to left until it reaches equilibrium, after that a double arrow is used.

2H₂O ↔ 2H₂ + O₂

While writing an equation, always place the reactant on the left and the products on the right even within the case of a reversible reaction.

A chemical equation represents not just the reaction, other than also displays the number of atoms or molecules entering within and generates through the reaction. The formulas must be balanced properly based on the valences of the constituent elements.