Calculate the enthalpy of combustion (kJ/mol) of methyl linoleate (C₁₉H₃₄O₂)

Question

Calculate the enthalpy of combustion (kJ/mol) of methyl linoleate (C₁₉H₃₄O₂), an important component of many biodiesel fuels made from corn oil and methanol, given the following standard enthalpies of formation:

CO₂(g) = -393.5 kJ/mol

H₂O(l) = -285.8 kJ/mol

C₁₉H₃₄O₂(l) = -645.7 kJ/mol

Answer 1

The balanced equation for the combustion of C19H34O2 ( ΔH) is

 2 C19H34O2(l) + 53 O2 (g) ===> 38 CO2(g) + 34 H2O) (g)

ΔH = sum ΔH_f products – sum ΔH_f reactants

ΔH = (38 x -393.5  + 34 x -285.8) – ( 2 x -645.7)

ΔH = (-246702 kJ –(-1291.4)kJ = -245411 kJ or -122706 kJ / mole