Explain why it is always necessary to balance a chemical equation. Be sure to discuss atoms, bonds, and the Law of Conservation of Mass

All chemical reactions follow the law of conservation of mass. This means that the number of atoms of a specie before the reaction must equal to the number of atoms of that specie after that reaction. The only change that occurs in chemical reactions is the breaking and formation of chemical bonds, due to which energy may be released or absorbed.

According to the Law of Conservation of Mass, chemical equations must always be balanced because matter cannot be created or destroyed. The bonds between the atoms may change throughout and after the reaction, but they (the mass) cannot be created or destroyed.