aA + bB → cC + dD

where:

A, B, C, and D are the chemical formulas of the reactants and products, respectively.

a, b, c, and d are the coefficients of the reactants and products, respectively.

The coefficients indicate the relative number of moles of each substance that are involved in the reaction. For example, if a = 2, then 2 moles of A are required for the reaction.

The arrow (→) indicates the direction of the reaction. In this case, the reaction is proceeding from left to right, meaning that A and B are reacting to form C and D.