Balance Li_3N+NH_4NO_3→LiNO_3+(NH_4)_3N

The law of conservation of mass states that matter cannot be created nor destroyed. There are no more or less atoms at the end of a chemical reaction than there were at the beginning. To balance a chemical equation, every element must have the same number of atoms on each side of the equation.

${\displaystyle Li}$ is not a balanced element. To balance ${\displaystyle Li}$, multiply ${\displaystyle LiN{O}_3}$ from the right side by ${\displaystyle 3}$.

${\displaystyle N}$ is not a balanced element. To balance ${\displaystyle N}$, multiply ${\displaystyle N{H}_{4}N{O}_3}$ from the left side by ${\displaystyle 3}$ and from the right side by ${\displaystyle 3}$.

${\displaystyle H}$ is a balanced element because there is the same number of atoms of ${\displaystyle H}$ in each side of the equation.

${\displaystyle O}$ is a balanced element because there is the same number of atoms of ${\displaystyle O}$ in each side of the equation.