phosphorus burns in the limited supply of air to form phosphorus(iii)oxide, P4O6 and in unlimited supply of air to form phosphorus(v)oxide P4O10. If 3.3g of phosphorus(iii)oxide is formed what mass of oxygen from air is used

Consider the reaction: 2al(s) + fe2o3(s) → al2o3(s) + 2fe(s) the δhf for fe2o3(s) = -824.3 kj/mole. the δhf for al2o3(s) = -1675.7 kj/mole. finish the equation. δhrxn = [(1)( kj/mole) + (2)( kj/mole)] - [(1)( kj/mole) + (2) ( kj/mole)]