## Chemistry: Principles and Practice (3rd Edition)

$4Fe (s) + 3O_{2} (g) → 2Fe_{2}O_{3}$ Oxidation numbers in reactants: Fe = 0, O2 = 0 Oxidation number in products: Fe = +3, O = -2 From above, we observe that oxygen is reduced (0 to -2), and Iron is oxidized (0 to +3)
$4Fe (s) + 3O_{2} (g) → 2Fe_{2}O_{3}$ Oxidation numbers in reactants: Fe = 0, O2 = 0 Oxidation number in products: Fe = +3, O = -2 From above, we observe that oxygen is reduced (0 to -2), and Iron is oxidized (0 to +3)