4Fe + 3O₂ ⇒ 2Fe₂O₃
4*56g Fe.......................2*160g Fe₂O₃
112g Fe................................xg Fe₂O₃
x = (2*160*112)/(4*56) = 160g Fe₂O₃
4*56g Fe...................3 moli O₂
112g Fe.....................x moli O₂
x = (3*112)/(4*56) = 1,5 moli O₂