Chemical Thermodynamics Question 308
Question: The enthalpies of combustion of carbon and carbon monodie are -393.5 and -283 kJ mol-1 respectivley. The enthalpy of formation of carbon monoxide per mole is [AIEEE 2004]
Options:
A) $ -676.5,kJ $
B) $ 676.5,kJ $
C) $ 110.5,kJ $
D) $ -110.5,kJ $
Show Answer
Answer:
Correct Answer: D
Solution:
$ C(s)+O_2(g)\to CO_2(g) $
$ \Delta H=-393.5,KJ,mo{{l}^{-1}} $ -..(i) $ CO(g)+1/2O_2(g)\to CO_2(g) $
$ \Delta H=-283,KJ,mo{{l}^{-1}} $ -..(ii)
On substracting equation (ii) from equation (i) We get
$ C(s)+O_2(g)\to CO(g) $ ; $ \Delta H=-110.5,KJ,mo{{l}^{-1}} $
The enthalpy of formation of carbon monooxide per mole $ =-110.5,KJ,mo{{l}^{-1}} $
