First we need to construct the equation of the combustion: C2H5OH(l) + 3O2(g) --> 2CO2(g) + 3H2O(l)Use aid of structural formulaLeft hand side (endothermic - requires energy):5(413) + 347 + 358 + 464 + 3(498) = 4728 kJ Right hand side (exothermic - releases energy):-[6(464) + 4(805)] = -6004 kJEnthalpy of combustion = 4728 - 6004 = -1276 kJ/mol