A balanced chemical equation obeys the law of?

A balanced chemical equation obeys the law of conservation of mass. This means that in a chemical reaction, the total mass of the reactants (the substances being combined) must equal the total mass of the products (the substances formed by the reaction). This law is based on the idea that atoms cannot be created or destroyed in a chemical reaction, they can only be rearranged to form new substances. Therefore, the number and types of atoms present in the reactants must be the same as the number and types of atoms present in the products. By balancing the chemical equation, we ensure that the number of atoms of each element is the same on both sides of the equation, and thus the total mass is conserved.