Yes, this is a balanced chemical equation, and it obeys the Law of Conservation of Mass.
A balanced chemical equation obeys the Law of Conservation of Mass if there are the same numbers of each type of atom on each side of the reaction arrow.
N₂ + 3H₂ ⟶ 2NH₃
Let’s check the numbers.
Atom On the left On the right
N 2 2
H 6 6
We have the same numbers of H and O on each side of the reaction arrow.
The equation is balanced and it obeys the Law of Conservation
of Mass.
