Chapter 15 : Activities and Activity coefficients

Example 15.1 Page No : 357

In [1]:
# Variables
p1 = 17.222 			#mm
p2 = 17.535 			#mm
n = 1.       			#mole
m = 1000 	    		#gms
M = 18.016 		    	#gms

# Calculations
a = p1/p2
N1 = (m/M)/(n+(m/M))

# Results
print  'activity  = %.4f '%(a)
print  ' activity coefficient  = %.4f '%(N1)

activity  = 0.9821 
 activity coefficient  = 0.9823

Example 15.2 Page No : 361

In [2]:
# Variables
import math 
M = 0.1 			#molal
Tf = 0.345 			#C
k = -9.702*10**-3
k1 = -5.2*10**-6

# Calculations
a = math.e**(k*Tf+k1*Tf**2)

# Results
print  'activity  = %.4f '%(a)

activity  = 0.9967

Example 15.3 Page No : 366

In [3]:
# Variables
import math 
R = 1.98*10**-4 			#cal mole**-1 deg**-1
T = 20.          			#C
E = -0.11118 	    		#volt
n2 = 0.00326
n21 = 0.0986

# Calculations
r = 10**((-E/(R*(273.16+T)))-math.log10(n21)+math.log10(n2))+n21
a2 = r*n21

# Results
print  'a2/N2  = %.3f '%(r)
print  ' a2  = %.4f '%(a2)

a2/N2  = 2.820 
 a2  = 0.2780

Example 15.4 Page No : 367

In [4]:
# Variables
n1 = 0.424 			#mole fraction
a2 = 3.268
n = 8.3

# Calculations
r = a2/(n*n1)

# Results
print  'a2/N2  = %.3f '%(r)

a2/N2  = 0.929

Example 15.5 Page No : 368

In [5]:
# Variables
e = 0.7865 	    		#volt
emf = 0.8085 			#emf
T = 500.    			#C
R = 1.98*10**-4 			#cal mol6-1 deg**-1
n2 = 0.5937

# Calculations
a2 = 10**((e-emf)/(R*(273+T)))
r = a2/n2

# Results
print  'activity coefficient  = %.2f '%(r)

activity coefficient  = 1.21

Example 15.6 Page No : 371

In [7]:
# Variables
import math 
ac = 1.211
n2 = 0.5937

# Calculations
b = math.log10(ac)/(1-n2)**2

# Results
print  'Constant  = %.4f '%(b)

Constant  = 0.5037
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