Page 114 - Modeling of Chemical Kinetics and Reactor Design

84 Modeling of Chemical Kinetics and Reactor Design

and

T ∆C
∆S = ∆S + ∫ p dT
o
o
s T
Ts
Hence,

cal
∆C =−15 455 +17 124 ×10 −3 T − 4 887 ×10 −6 T 2
.
.
.
p
mol K N
2
and
o
∆S = ( 2 4610. ) − 4587 3. − (31 29. )
s
cal
.
=− 47 54
mol K
•
This is the entropy change for a complete conversion to NH where
3
1 kmol of N is converted. The entropy change at 428 K is:
2

428 −15 455

.
o
.
.
.
∆S =− 47 54 + ∫   +17 124 ×10 −3 − 4 887 ×10 −6 TdT

298 T
428  T 2 
−3
.
.
=− 47 54 +  −15 455ln T +17 124 ×10 T − 4 887 ×10 −6 
.
.
298  2 
 428  −3
=−47 54 + −15 455ln +17 124 ×10 (428 − 298 )
.
[
.
.
 298 
)
.
− 4 887 ×10 −6 (428 2 −298 ]
2
2
+
−
=− 47 54 5 595 2 226 − 0 231
.
.
.
.
cal
=− 51 14
.
molK N 2