Balance Equations by Conserving Each Element

Conservation is an element-by-element check

A chemical equation lists reactant formulas on the left and product formulas on the right. In the chemical-reaction model, atoms are rearranged rather than changed into different elements. A balanced equation therefore contains the same number of each element’s atoms on both sides. A matching total number of atoms is insufficient if one element is too high and another too low. A matching number of molecules is not required: 2H₂+O₂→2H₂O has three reactant molecules for every two product molecules in the particle interpretation.