Chemical Thermodynamics Question 316
Question: Evaluate $ \Delta U $ at 500 K for the process $ Mg(s)+2HCl(g)\to MgCl_2(s)+H_2(g)\Delta H=-109 $ kcal The volume change of solids to be ignored
Options:
A) -204 kcal
B) -108 kcal
C) -9 kcal
D) +9 kcal
Show Answer
Answer:
Correct Answer: B
Solution:
- $ \Delta H=\Delta U+\Delta n_{g}RT $
$ -109=\Delta U+( \frac{-1\times 2\times 500}{1000} )kcal $
$ -109=\Delta U-1,kcal $
$ \Delta U=-109+1=-108,kcal $
