Calculation of the Viscosity coefficient and Potential Profile for CH3Cl

Follows derivations of L. Monchick and E.A. Mason, J.Chem. Phys. 9, 398 (1941)

 > restart;

Basic viscosity equation:

 > mu:= 5/16*(m*k*T/Pi)^(1/2)*fh/(sigma^2*Omega_[2,2]);

Correction term:

 > fh:= 1 + 3/196*(8*E - 7)^2;

For CH3Cl at T= 25 C and 1 atm:

 > k:= 1.38066e-16*erg/K; T:= 273*K;

Mass of one CH3Cl molecule:

 > m:= ((12.01 + 35.45 + 1.01*3)*g/mol) / (6.0221e23/mol);

Dimensionless temperature term:

 > Tstar:= k*T/epsilon;

Given values for CH3Cl in Monchiek and Mason:

where μd is the dipole moment, δ is polarity term, σ is minimum non-repulsive distance between two molecules,

and ε is lowest parameter energy

 > mu_[d]:= 1.87*debye; delta:= .5; sigma:= 3.94*Angstrom; epsilon:= 414*K*k;

 > Tstar;

Using the values for δ and T*, can find values for the collision integral and <E*> using tables in Monchiek and Mason:

 > Omega_[2,2]:= 2.000; E:= 0.8738;

 > fh;

 > mu;

 > erg:= g*cm^2/s^2; Angstrom:= 1e-08*cm;

 > mu_[p]:= simplify(mu) assuming g::positive, cm::positive, s::positive;

Accepted value is .0000989 Poise - (from Air Liquide)

Now to use the corrected non-polar model (based on Lennard-Jones potential and experimental evidence).

 > sigma_[lj]:= 4.151*Angstrom; epsilon_[lj]:= 355*K*k;

 > kTe:= k*T/epsilon_[lj];

 > Omega_[lj]:= 1.83;

 > mu_[lj]:= 5/16*sqrt(Pi*m*k*T)/(Pi*sigma_[lj]^2*Omega_[lj]);

 > mu_[lj]:= simplify(%) assuming g::positive, cm::positive, s::positive;

While this value is closer to the given value than the corrected viscosity equation, it only goes to show the advances in understanding of visosity.

In recent years the omega terms have undoubtedly been corrected to give more accurate values, as the given value evidences.  We were unable

to locate the more recent tables for polar viscosity, but the accuracy of the 60 year-old model shows the benefits of applying the non-polar

Chapman-Enskog theory over completely neglecting it.