Oxidation Reduction combination with O2 loss of O2 loss of electrons gain of electrons gain in oxidation loss in oxidation number number
An oxidation agent is a donor of electrons. A reduction agent is the absorber of electrons.
Fe2O3 + CO Fe + CO2 +3 -2 +2 -2 0 +4 -2 Write the oxidation numbers down Fe2O3 + CO Fe + CO2 +3 -2 +2 -2 0 +4 -2 Notice how the carbon's number changes Fe2O3 + CO Fe + CO2 and how the iron's number changes. Carbon gains two oxidation numbers, thus oxidizing. Iron is reducing as it loses three oxidation numbers. +3 -2 +2 -2 0 +4 -2 Write in coefficients so that the Fe2O3 + 3CO 2Fe + CO2 oxidation number changes cancel out.