Question

what is the limiting reactant if 0.10 moles Fe and 0.16 moles O2 react according to the reaction 4Fe +3O2 -> 2Fe2O3?

Answer 1

0.1 mol Fe x (2 mol Fe2O3/4 mol Fe) = 0.1 x 1/2 = 0.05 mol Fe2O3 produced if we had 0.1 mol Fe and all the O2 we needed.

0.16 mol O2 x (2 mol Fe2O3/3 mol O2) = 0.16 x 2/3 = 0.107 mol Fe2O3 produced if we had 0.16 mol O2 and all the Fe we needed.

So Fe must be the limiting reagent as that produces the least amount of Fe2O3.