# How many moles of iron (lll) nitrate are in 200 grams of iron (Ill) nitrate?

$\text{Number of moles}$ $=$ $\text{Mass"/"Molar mass}$
$n = \frac{200 \cdot g}{241.86 \cdot g \cdot m o {l}^{-} 1}$ $\cong$ $0.80 \cdot m o l$ $F e {\left(N {O}_{3}\right)}_{3}$.
How many moles of $O$, and $N$ does the given mass represent?