Question

The formula for rust can be represented by Fe2O3 How many moles of Fe are present in 14.2 g of the compound?

Answer 1

31.0 g Fe2O3 x (1 mole Fe2O3 / 159.7 g Fe2O3) = 0.194 moles Fe2O3  

In the formula Fe2O3, there are 2 Fe. So 1 mole of the compound Fe2O3 contains 2 moles of Fe.  

0.194 moles Fe2O3 x (2 mole Fe / 1 mole Fe2O3) = 0.388 moles Fe