Chapter14 Electromotive Force

Example 14.1,Page no.57

In [10]:
import math
#initialisation of variables
n=2.0
V=0.67533 # volt
E=23060 # cal volt ˆ−1
Tc=-6.5*10**-4 # volt degˆ−1
T=25.0 #C
#CALCULATIONS
G=-n*V*E 
S=n*E*Tc 
H=-n*E*V+n*Tc*E*(273+T)
#RESULTS
G=round(G,2)
S=round(S,2)
H=round(H,2)
print  'dG =',G,'cal'
print  'dS =',S,'cal degˆ−1'
print  'dH =',H,'cal'

dG = -31146.22 cal
dS = -29.98 cal degˆ−1
dH = -40079.66 cal

Example 14.3,Page no.57

In [2]:
import math
#initialisation of variables
C=0.01 #M
C1=0.02 #M
n=1
n1=2
#CALCULATION
I=0.5*(C*n**2+C**n**2)
I1=0.5*(C1*n**2+C*n1**2) 
I2=0.5*(C*n1**2+C*n1**2)
#RESULTS
print   'ionic strength of NaCl =',I
print   'ionic strength of Li2SO4 =',I1
print   'ionic strength of CuSO4 =',I2 

ionic strength of NaCl = 0.01
ionic strength of Li2SO4 = 0.03
ionic strength of CuSO4 = 0.04

Example 14.4,Page no.58

In [3]:
import math
#initialisation of variables
C=0.1 #M
V=0.3524 # volt
V1=0.2224 # volt
V2=0.1183 # volt
#CLACULATIONS
r=10**((-V+V1+V2)/V2)
#RESULTS
r=round(r,3)
print 'mean ionic activity=',r

mean ionic activity= 0.796

Example 14.5,Page no.58

In [4]:
import math
#initialisation of variables
n=2
F=96500 # coloumbs 
E=0.337 # volt 
E1=-0.403 # volt 
#CALCULATIONS 
E0=E-E1
G=-n*F*E0/4.184
G=round(G,2)
#RESULTS
print 'voltage of cell =',E0,'volt'
print 'gibbs free energy=',G,'cal'

voltage of cell = 0.74 volt
gibbs free energy= -34134.8 cal

Example 14.6,Page no.59

In [5]:
import math
#initialisation of variables
E=-0.403 # volt 
E1=-0.763 # volt 
#CALCULATIONS 
E0=E-E1 
#RESULTS
print 'voltage of cell =',E0,'volt'

voltage of cell = 0.36 volt

Example 14.7,Page no.59

In [11]:
import math
#initialisation of variables
E=1.360 # volt 
E1=0.337 # volt 
F=965000 # coloumbs 
#CALCULATIONS 
G=-F*(E-E1)/4.1840 
#RESULTS
G=round(G,1)
print 'Gibbs free energy =',G,'cal'

Gibbs free energy = -235945.3 cal

Example 14.8,Page no.60

In [7]:
import math
#initialisation of variables
E=-0.126 # volt 
E1=-0.140 # volt 
n=2.0 
R=0.0591 # volt 
#CALCULATIONS 
E0=E-E1 
K=10**((E-E1)*n/R) 
#RESULTS
K=round(K,3)
print 'equilibrium constant =',K 

equilibrium constant = 2.977

Example 14.9,Page no.60

In [8]:
import math
#initialisation of variables
E0=0.0140 # volt 
n=2.0 
r=2.0 
V=96500.0 # coloumbs 
#CALCULATIONS 
E=E0-0.0576*math.log10(n) 
G=-n*V*E/4.1840
#RESULTS 
G=round(G,3)
print 'gibbs free energy =',G,'cal'

gibbs free energy = 154.037 cal

Example 14.10,Page no.60

In [9]:
import math
#initialisation of variables
n=2.0 
R=0.0591 
C=0.01 #M 
C1=0.1 #M 
#CALCULATIONS 
E=-R*math.log10(C/C1)/n 
#RESULTS 
E=round(E,4)
print 'electromotive force of the cell =',E,' volt'

electromotive force of the cell = 0.0295  volt