Which of the following chemical equations shows the Law of Conservation of Mass?

Responses

N2+H2→NH3
K+MgBR→KBR+Mg
P+O2→P2O5
H2O+O2→H2O2

The chemical equation "N2+H2→NH3" shows the Law of Conservation of Mass as the number of atoms of each element is the same on both sides of the equation.