# What mass of ammonia constitutes a volume of 22.4*dm^3 at "STP"?

$22.4 \cdot {\mathrm{dm}}^{3}$ of ammonia at $\text{STP}$ specifies a mole of ideal gas............
So if we treat ammonia as an ideal gas, there are $\left(14.01 + 3 \times 1.00794\right) \cdot g$ of $N {H}_{3} \left(g\right)$