Chemical Thermodynamics Question 260
Question: Given that $ C(s)+O_2(g)\to CO_2(g),\Delta H=-394kJ $
$ 2H_2(g)+O_2(g)\to 2H_2O(l),,\Delta H=568kJ $
$ CH_4(g)+2O_2(g)\to CO_2(g)+2H_2O(l) $
$ \Delta H=-892,kJ $ Heat of formation of $ CH_4 $ is [DCE 1999]
Options:
A) - 70 kJ
B) 71.8 kJ
C) - 244 kJ
D) + 782 kJ
Show Answer
Answer:
Correct Answer: A
Solution:
$ C+O_2\to CO_2,\Delta H=-394,kJ $ -..(i) $ 2H_2+O_2\to 2H_2O,,\Delta H=-568,kJ $ -.(ii) $ CH_4+2O_2\to CO_2+2H_2O,,\Delta H=-892,kJ $ -..(iii) (i) + (ii) - (iii) and find the required result.
