Chemical Thermodynamics Question 321
Question: $ C_2H_6(g)+3.5O_2(g)\to 2CO_2(g)+3H_2O(g) $
$ \Delta S_{vap}(H_2O,\ell )=x_1cal,{{K}^{-1}} $ (boiling point = $ T_1 $ ) $ \Delta H_{f}(H_2O,\ell )=x_2 $
$ \Delta H_{f}(C_2O,)=x_2 $
$ \Delta H_{f}(C_2H_6,)=x_4 $
Hence, $ \Delta H $ for the reaction is
Options:
A) $ 2x_3+3x_2-x_4 $
B) $ 2x_3+3x_2-x_4+3x_1T_1 $
C) $ 2{{x}^{+}}+3x_2-x_4+3x_1T_1 $
D) $ x_1T_1+x_2+x_3-x_4 $
Show Answer
Answer:
Correct Answer: B
Solution:
- $ H_2O(l)\to H_2O(g)\Delta H_{vap}=\Delta S_{vap}{T_{B.P.}}=x_1T_1 $
$ \Delta H_{f}(H_2O,g)=\Delta H_{f}(H_2O,1)+\Delta H_{vap}=x_2+x_1T_1 $
$ \Delta H_{reaction}=2\Delta H_{f},(CO_2,g)+3\Delta H_{f}(H_2O,g)-\Delta H_{f}(C_2H_6,g) $
$ =2x_3+3(x_2+x_1T_1)-x_4=2x_3+3x_2+3x_1T_1-x_4 $
