Sulphur burns in air to form sulphur (IV) oxide. A simple energy level diagram for the reaction is given below. Study the diagram and answer the questions the follows Enerav S. + O2 (g) (g) AH SH Reaction co-ordinate 1 1 AH SO2(gl (a) What do the following represents? AH1 and AH3 (2 mks) (b) Write an expression for AH3 and in terms of A H1 and AH2 (1 mk)