Finding how much net energy is absorbed relased? (Chemistry)

Question

Hi, I need help with finding the net energy absorbed or relased by : C+O2 ----> C02 . 

 

I know the bond energies for oxygen and carbon dioxide. But just the carbon, is there any bond energy? In my calculations, what do I leave carbon as?

Answer 1

For reference, the standard heat of formation of carbon dioxide is -393.5 kJ/mol

 

You can calculate the value as follows:

 

C(s) -->  C(g)     enthalpy of atomization is 717 kJ/mol

 

O2  -->  2 O       bond dissociation energy is 498 kJ/mol

 

C(g) + 2 O -->  CO2   total bond dissociation energy is 2 (805 kJ/mol)

 

Total heat energy released during the reaction is  -717 kJ/mol - 498 kJ/mol + 1610 kJ/mol = 395 kJ/mol