blob: fc3c8493d2ebbf59cc838d6ee7fc2cd9bf93abf3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
|
//(13.10) Determine the change in entropy of the system of Example 13.6 in kJ/K.
//solution
Rbar = 8.314 //universal gas constant in SI units
//The chemical equation for the complete combustion of methane with oxygen is
//CH4 + 2O2 ----> CO2 + 2H2O
yCH4 = 1/3
yO2 = 2/3
yCO2 = 1/3
yH2O = 2/3
//from table A-25
sbarCH4atTref = 186.16 //in kj/kmol.K
sbarO2atTref = 205.03 //in kj/kmol.K
sbarCH4 = sbarCH4atTref - Rbar*log(yCH4)
sbarO2 = sbarO2atTref - Rbar*log(yO2)
p2 = 3.02 //in atm
pref = 1 //in atm
//with help from table A-23
sbarCO2 = 263.559 - Rbar*log(yCO2*p2/pref) //in kj/kmol.K
sbarH2O = 228.321 - Rbar*log(yH2O*p2/pref) //in kj/kmol.K
deltaS = sbarCO2 + 2*sbarH2O - sbarCH4 -2*sbarO2 //in kj/K
printf('the chenge in entropy of the system in kJ/K is: %f',deltaS)
|
