# Chapter 6 Real Gas and Transport Processes in gas¶

## EXample 6.1 Page no 89¶

In :
#given
a=(2.1*10**-2)                                          #Vanderwaals constant a for neon gas in Nm^4/mol^2
b=(1.71*10**-5)                                         #Vanderwaals constant b for neon gas in m^3/mol
R=8.314                                                 #Gas constant in J/mol.K

#Calculations
Tc=(8*a)/(27*b*R)
Vc=(3*b)/10.0**-5
Pc=(a/(27*b**2))/10.0**6

#Output
print"Critical temperature is ",round(Tc,2),"K"
print"Critical volume is ",round(Vc,2),"* 10**-5 m**3/mol"
print"Critical pressure is ",round(Pc,3),"* 10**6 N/m**2"

Critical temperature is  43.77 K
Critical volume is  5.13 * 10**-5 m**3/mol
Critical pressure is  2.66 * 10**6 N/m**2


## Example 6.2 Page no 89¶

In :
#given
n=181*10**-6                                           #Coefficient of viscosity of a gas in p
v=3*10**4                                              #Average speed of molecules in cm/s
d=1.2929*10**-3                                        #Density in g/cm^3

#Calculations
lembda=((3*n)/(d*v))/10**-6

#Output
print"Mean free path is ",round(lembda,0),"* 10^-6 cm"

Mean free path is  14.0 * 10^-6 cm


## Example 6.3 Page no 89¶

In :
#given
m=(28*1.66*10**-27)                                     #Molecular mass of a gas in kg
d=(3.48*10**-10)                                        #Diameter in m
k=(1.38*10**-23)                                        #Boltzmans constant in J/K
P=1.01*10**5                                            #Pressure at STP in N/m^2
T=273                                                   #Temperature at STP in K

#Calculations
import math
D=((1/(P*3*d**2*math.sqrt(m)))*((2*k*T)/3.14)**(3/2.0))/10.0**-5

#Output
print"Diffusion coefficient of a gas at STP is ",round(D,2),"* 10**-5 m^2/s"

Diffusion coefficient of a gas at STP is  1.49 * 10**-5 m^2/s


## Example 6.4 Page no 89¶

In :
#given
m=(32*1.66*10**-27)                                      #Molecular mass of a gas in kg
d=(3.65*10**-10)                                         #Diameter in m
k=(1.38*10**-23)                                         #Boltzmans constant in J/K
P=1.01*10**5                                             #Pressure at STP in N/m^2
T=273                                                    #Temperature at STP in K

#Calculations
import math
n=((1/(3.14*d**2))*math.sqrt((8*k*T*m)/(9*3.14)))/10**-5

#Output
print"Viscosity of a gas at STP is ",round(n,3),"*10^-5 N.s/m^2"

Viscosity of a gas at STP is  1.799 *10^-5 N.s/m^2


## Example 6.5 Page no 89¶

In :
#given
v=460                                                #Average speed of molecules in m/s
l=(720*10**-10)                                      #Mean free path in m
Cv=21.06                                             #Specific heat at constant volume in J/K.mol
k=(1.38*10**-23)                                     #Boltzmans constant in J/K
P=1.01*10**5                                         #Pressure at STP in N/m^2
T=273                                                #Temperature at STP in K

Thermal conductivity of the gas at STP is  1.03506 *10**-2 W/m-K