wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

What is the value of the change in internal energy at 1 atm in the following process?
H2O(l,323 K)H2O(g,423 K)
Given : Cv,m(H2O,1)=75.0 JK1;Cp,m(H2O,g)=33.314JK1mol1;ΔHvapat373K=40.7kJ/mol

A
42.910 kJ/mol
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
43.086 kJ/mol
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
42.600 kJ/mol
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
49.600 kJ/mol
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 42.600 kJ/mol
We can break it down into three parts.
(i) H2O(l,323 K)H2O(l,373 K)
(ii) H2O(l,373 K)H2O(g,373 K)
(iii) H2O(g,373 K)H2O(g,423 K)
now,
in(i),
q=nCvT=1×75×50=3750 J=3.75 kJ
w: negligible.
E=3.75 kJ
in (ii),
q=mL=Hvap=40.7 kJ
w=PextV=105 Pa(22.4×373273×103m3)
=3.06 kJ
E=+37.64 kJ

in (iii)
q=nCpT=1×33.314×50
=1.666 kJ
ω=105 Pa(22.4×42327322.4×373273)×103
=0.410 kJ
E=+1.256 kJ
Etotal=+42.646 kJ

flag
Suggest Corrections
thumbs-up
9
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Heat Capacity
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon