Chemical Thermodynamics Question 480
Question: The difference between the heats of reaction at constant pressure and a constant volume for the reaction $ 2C_6{H_{6( 1 )}}+15{O_{2(g)}}\xrightarrow{{}}12C{O_{2(g)}}+6H_2{O_{(I)}} $ in Kj is :
Options:
A) - 7.43
B) + 3.72
C) - 3.72
D) + 7.43
Show Answer
Answer:
Correct Answer: A
Solution:
- $ \Delta H=\Delta E+\Delta n_{g}RT $
Here $ \Delta n_{g}=12-15=-3 $
Thus, $ \Delta H-\Delta E=-3\times 8.314\times 298=-7.43kJ $
