# How many moles of S are in 125 g of SO_2?

Approx. $2$ $m o l$.
$S {O}_{2}$ has a molecular weight of $64.07$ $g \cdot m o {l}^{-} 1$.
You specified $125 \cdot g$ of stuff:
So $\frac{125 \cdot \cancel{g}}{64.07 \cdot \cancel{g} \cdot m o {l}^{-} 1}$ $=$ ?? mol???