# How many moles of N are in 0.217 g of N_2O?

There are twice the molar quantity of nitrogen atoms in nitrous oxide, i.e. $1 \times {10}^{-} 2 \cdot m o l$.
$\text{Moles of nitrous oxide}$ $=$ $\frac{0.217 \cdot g}{44.013 \cdot g \cdot m o {l}^{-} 1}$ $=$ $5 \times {10}^{-} 3 \cdot m o l$.
Given the composition of ${N}_{2} O$, there are this $2 \times 5 \times {10}^{-} 3 \cdot m o l$ of nitrogen atoms.