Chemical Thermodynamics Question 304
Question: The heat of combustion of carbon to $ CO_2 $ is $ -393.5,kJ/mol $ . The heat released upon formation of 35.2 g of $ CO_2 $ from carbon and oxygen gas is [UPSEAT 2004]
Options:
A) $ +,315,kJ $
B) $ -,31.5,kJ $
C) $ -315,kJ $
D) $ +31.5,kJ $
Show Answer
Answer:
Correct Answer: C
Solution:
$ C+O_2\to CO_2\Delta H=-393.5,KJ/mol $
$ \because $ $ 44,gm $ of $ CO_2 $ form by which heat released $ =-393.,5,kJ $
$ \therefore $ $ 1gm $ of $ CO_2 $ form by which heat released $ =-\frac{393.5}{44} $
$ \therefore $ $ 35.2,gm $ (given) of $ CO_2 $ form by which heat released $ =-\frac{393.5}{44}\times 35.2 $
$ =-315,kJ $
