Question

A 89,6g sample of Fe(s) is mixed with 33,6 dm^3 of oxygen gas at STP

Answer 1

$$4Fe + 3O_2 = 2Fe_2O_3$$

$$n(Fe) = m/M = 89.6/55.8 = 1.6 mol$$

$$n(O_2) = V/V_m = 33.6/22.4 = 1.5 mol$$