energy released from co combustion?

C & O2 --> CO2 is the dH formation reaction for CO2 ...

dHf CO2 = -393.5 kJ/mole

-----------------

youir first question:from c-co how much energy is released?

is the dHf reaction for CO:

C & 1/2 O2 --> CO

dHf CO = -110.5 kJ/mole

that answer is straight out of the back of the book, themodynamic quantities...

-========================================

your next question "from co-co2 how much energy is released":

uses Hess's law ,

it comares the above 2 reactions and says the difference in energies is due to:

CO & 1/2O2 --> CO2

and that difference -393.5 - (-110.5) gives ...

your answer of -283 kJ/ mole