Chemical Thermodynamics Question 42
Question: The entropy changed involved in the conversion of 1 mole of liquid water at 373 K to vapour at the same temperature will be $ [\Delta {H_{vap}}=2.257kJ/gm] $ [MP PET 2002]
Options:
A) 0.119 kJ
B) 0.109 kJ
C) 0.129 kJ
D) 0.120 kJ
Show Answer
Answer:
Correct Answer: B
Solution:
$ H_2{O_{(l)}} $ ⇌ $ H_2{O_{(g)}},,\Delta S=\frac{\Delta H_{vap}}{T}, $
$ \Delta {H_{vap.}}=2.257,KJ/g $ or $ \Delta H_{vap}=2.257\times 18,kJ/mol.,=40.7,KJ/mol $
hence, $ \Delta S=\frac{40.7}{373}=0.109,kJ/mol/K. $
