Calculate the enthalpy of formation of acetic acid if its anthalpy of combustion to CO2 and H2O is - 867 kJ/mol and the enthalpies of formation of CO2 and H2O are respectively - 393.5 and -285.9 kJ / mol ?

1 Answer
Nov 12, 2016

Answer:

-491.8kJ/mol

Explanation:

Combustion reaction for above question is

#C_2H_4O_2 + 2O_2 -> 2CO_2 + 2H_2O#

#DeltaH_f(combustion) = 2[DeltaH_(CO_2) + DeltaH_(H_2O)] - DeltaH_(C_2H_4O_2)#

#DeltaH_(C_2H_4O_2) = 2[DeltaH_(CO_2) + DeltaH_(H_2O)] -DeltaH_(combustion)#

#DeltaH_(C_2H_4O_2) = 867+(2times-679.4) = -491.8(kJ)/(mol)#