Question

How many moles of iron atoms are in

15.03 g of iron (II) sulfide, FeS?

Answer 1

Molar mass of FeS = $87.91\ g\ mol^{-1}$

Moles of $FeS$ in $15.03\ g=\frac{15.03}{87.91}=0.171\ mole$

Moles of iron atom =Moles of $FeS=0.171\ mole$