Please help explain!!1 The combustion of methane, CH4, releases 890.4 kJ/mol. That is, when one mole of methane is burned, 890.4 kJ are given off to the surroundings. This means that the products have 890.4 kJ less than the reactants. Thus, ΔH for the reaction = - 890.4 kJ. A negative symbol for ΔH indicates an exothermic reaction. CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (l); ΔH = - 890.4 kJ a) How much energy is given off when 2.00 mol of CH4 are burned? b) How much energy is released when 22.4g of CH4 are burned?