# Chapter 8 : Entropy relationships and applications¶

## Example 8.1 Page No : 155¶

In [1]:
# Variables
import math
k1 = 6.2
k2 = 1.33*10**-3
k3 = 6.78*10**4
T1 = 800. 			#C
T2 = 300. 			#C

# Calculations
dS = k1*math.log(T1/T2)+k2*(T1-T2)-0.5*k3*(T1**-2-T2**-2)

# Results
print  'Entropy increase  = %.2f cal deg**-1 g atom**-1'%(dS)

Entropy increase  = 7.07 cal deg**-1 g atom**-1


## Example 8.2 Page No : 159¶

In [2]:
# Variables
T = 77.32 			#K
p = 1    			#atm
Tc  = 126 			#K
Pc = 33.5 			#atm
Mo = 32 			#gms
mo = 27 			#gms
R = 1.98 			#cl/mol K

# Calculations
dS = (mo)*R*Tc**3/(Mo*Pc*T**3)

# Results
print  'Entropy increase  = %.3f cal deg**-1'%(dS)

Entropy increase  = 0.216 cal deg**-1


## Example 8.3 Page No : 160¶

In [3]:
# Variables
R = 1.987 			#cal deg**-1 mole**-1
T = 25   			#C
Pc = 49.7 			#atm
m = 128 			#gms
pc = 49.7 			#atm
Tc = 154.3 			#K
m1 = 9 	    		#gms
m2 = 18

# Calculations
dH = (m1*R*Tc/(m*pc))*(1-m2*(Tc/(273.15+T))**2)*-1

# Results
print  'Enthalpy  = %.2f cal mole**-1'%(dH)

Enthalpy  = 1.66 cal mole**-1


## Example 8.4 Page No : 165¶

In [4]:
# Variables
a = 1.39 			#lit**2
p = 200. 			#atm
R = 0.082 			#lit-atm /mol K
T = 298. 			#K

# Calculations
dC = (1+(2*a*p/(R*T)**2))

# Results
print  'Cp-Cv  = %.2f *R lit-atm mole**-1 K**-1'%(dC)

Cp-Cv  = 1.93 *R lit-atm mole**-1 K**-1


## Example 8.5 Page No : 165¶

In [5]:
# Variables
P = 200. 			#atm
Tc = 126. 			#k
T = 25. 			#C
Pc = 33.5 			#atm
M = 27. 			#gms
m = 16. 			#gms

# Calculations
dC = (1+(M*Tc**3*P/(m*Pc*(273.2+T)**3)))

# Results
print  'Cp-Cv  = %.2f *R cal mole**-1 K**-1'%(dC)

Cp-Cv  = 1.76 *R cal mole**-1 K**-1


## Example 8.6 Page No : 167¶

In [6]:
# Variables
T = 25.          			#C
b = 0.785*10**-6 			#atm**-1
a = 49.2*10**-6 			#deg**-1
d = 8.93 		        	#gm/cc
aw = 63.57 			        #gms

# Calculations
dC = a**2*(273.2+T)*aw*0.0242/(b*d)

# Results
print  'Cp-Cv  = %.3f cal deg**-1g atom**-1'%(dC)

Cp-Cv  = 0.158 cal deg**-1g atom**-1


## Example 8.7 Page No : 169¶

In [7]:
# Variables
import math
p = 100 			#atm
T = 25.  			#C
a = 1.38
b = 3.92*10**-2 			#lit atm
R = 0.082 			#lit-atm mole**-1 K**-1
Tc = 126 			#K
Pc = 33.5 			#atm
M = 81. 			#gms
m = 32. 			#gms

# Calculations
dC = a*2*p/(R*(273+T)**2)
dC1 = M*R*Tc**3*p/(m*Pc*(273+T)**3)

# Results
print  'Cp-Cp*  = %.3f lit atm deg**-1 mole**-1'%(dC)
print  ' Cp-Cp*  = %.3f lit atm deg**-1 mole**-1'%(dC1)

Cp-Cp*  = 0.038 lit atm deg**-1 mole**-1
Cp-Cp*  = 0.047 lit atm deg**-1 mole**-1


## Example 8.8 Page No : 172¶

In [8]:
# Variables
Cp = 8.21*0.0413 			#lit-atm deg**-1 mole**-1
V = 8.64*28*10**-3 			#lit
r = 1.199

# Calculations
u = V*(r-1)/Cp

# Results
print  'Joule-thomson coefficient  = %.3f deg atm**-1'%(u)

Joule-thomson coefficient  = 0.142 deg atm**-1


## Example 8.9 Page No : 173¶

In [9]:
# Variables
Cp = 8.21*0.0413 			#lit-atm
R = 0.0821 			#lit-atm deg**-1 mole**-1
p = 100 			#atm
T = 20. 			#C
a = 1.39
b = 3.92*10**-2 			#lit-atm**2 mole

# Calculations
u = (1/Cp)*((2*a/(R*(273+T)))-b-(3*a*b*p/(R**2*(273+T)**2)))

# Results
print  'Joule-thomson coefficient  = %.3f deg atm**-1'%(u)

Joule-thomson coefficient  = 0.142 deg atm**-1

In [ ]: