Chemical Thermodynamics Question 233
Question: Carbon and carbon monoxide burn in oxygen to form carbon dioxide according to the following reactions $ C+O_2\to CO_2;,\Delta H=-394,kJ,mo{{l}^{-1}} $
$ 2CO+O_2\to 2CO_2;,\Delta H=-569,kJ,mo{{l}^{-1}} $ The heat of formation of $ 1,mol $ of carbon monoxide is thus [MP PET 1995]
Options:
A) $ -219.0,kJ,mo{{l}^{-1}} $
B) $ -109.5,kJ,mo{{l}^{-1}} $
C) $ -175.0,kJ,mo{{l}^{-1}} $
D) $ -87.5,kJ,mo{{l}^{-1}} $
Show Answer
Answer:
Correct Answer: B
Solution:
$ C+O_2\to CO_2+394,kJ $ . $ 2C+2O_2\to 2CO_2+788,kJ $ -.(i) $ 2CO+O_2\to 2CO_2+569,kJ $ -.(ii) $ 2CO_2\to 2CO+O_2-569,kJ $ -..(iii) eq. (i) + eq. (iii) = -109.5 kJ mol-1.
