Chapter19 Statistical Mechanics

Example 19.1,Page no.73

In [1]:
import math
#initialisation of variables
Na=1
Nb=1
Nc=1
Na1=2
Nb1=1
Nc1=0
Na2=3 
Nb2=0 
Nc2=0 
#CALCULATIONS 
Wabc=math.factorial(Na+Nb+Nc)/(math.factorial(Na)*math.factorial( Nb)*math.factorial(Nc))
Waab=math.factorial(Na1+Nb1+Nc1)/(math.factorial(Na1)*math.factorial(Nb1)*math.factorial(Nc1))
Waaa=math.factorial(Na2+Nb2+Nc2)/(math.factorial(Na2)*math.factorial(Nb2)*math.factorial(Nc2))
#RESULTS
print 'Wabc =',Wabc
print 'Waab =',Waab
print 'Waaa =',Waaa
Wabc = 6
Waab = 3
Waaa = 1

Example 19.2,Page no.74

In [2]:
import math
#initialisation of variables
K=4.9860 # cal degˆ−1 moleˆ−1
K1=-31.6 # cal degˆ−1 moleˆ−1
#CALCULATIONS
S=K-K1
#RESULTS
S=round(S,3)
print 'Enthalpy =',S,'cal degˆ−1 moleˆ−1'
Enthalpy = 36.586 cal degˆ−1 moleˆ−1

Example 19.4,Page no.74

In [3]:
import math
#initialisation of variables
No=0.979889
v=2989.74 #cmˆ−1
rc=1.2746 #A
T=25 #C
E1=6.8635 # cal degˆ−1 moleˆ−1
E2=11.4392 # cal degˆ−1 moleˆ−1 
E3= 7.2820 # cal degˆ−1 moleˆ−1 
E4= 4.5757 # cal degˆ−1 moleˆ−1 
E5= 2.7676 # cal degˆ−1 moleˆ−1 
r1= 0.265 #A 
r= 35.99 #A 
#CALCULATIONS 
Et=E1*math.log10(r)+E2*math.log10 (273.15+T)-E3
Ei=E4*math.log10(r1)+E4*math.log10 (273.15+T)-E5
#RESULTS
Et=round(Et,3)
Ei=round(Ei,3)
print 'Transitional energy',Et,'cal degˆ−1 mole ˆ−1'
print 'rotational energy =',Ei,'cal degˆ−1 mole ˆ−1'
Transitional energy 31.704 cal degˆ−1 mole ˆ−1
rotational energy = 5.916 cal degˆ−1 mole ˆ−1