Solution



Back 		Step 1
Required: Heat of formation of carbon monoxide.


Step 2
Write out given information.
Equation 1:
 (= -393 kJ)
Equation 2:
 (= -570 kJ)

Step 3
Rearrange
Equation 1 (1):
(= -393 kJ)
Equation 2 (Reverse and divide by 2):
(= +285 kJ)
( = -108 kJ )