
79Reviews of Thermodynamics
∆ss sC=−=−
21
900
0 2598
150
po
ln ln.
= 1.00306 × 1.0986 + 0.1800
Δs = 1.2819 kJ/kg · K.
Entropy change based on Equation 3.56a:
∆ss s
M
ss R
P
P
TT
=−=−
()
−
21
00
2
1
1
2
21
O
ln
.
From Table C.7:
and
∆ 239.931 205.329 8.3145 lns
M
=−−
1 150
300
2
O
∆s =+
1
34 602 5 7631 40 3651
(. .).kJ/kg K
Δs = 1.2614 kJ/kg · K.
Change of Gibbs Free Energy:
Change in Gibbs energy based on Equation 4.42c:
Δg = Δh – TΔs
599.61
900+ 300
1.2614 kJ kg
g =−
kj/k
Δg = 157.23 kJ/kg K.
3.11 Mixture of Gases
Operations of most fuel cell power systems involve a mixture of gases. ...