How many moles of iron are needed to form 8 moles of iron lll oxide? With 4 Fe + 3 O2 = 2 Fe2O3

Question

 i really just don't understand how to do these problems :/

Answer 1

First check that the chemical equation for the combustion of iron is balanced. Then using the balanced equation set up a ratio between iron and iron (III) oxide. From the equation you know that 4 moles of iron react to give 2 moles of iron (III) oxide. This should help you determine how many moles of iron are required.