Diffusivity of Water versus Sarin in Air at 10 Degrees Celsius (50 Degrees Fahrenheit) and 1 Atmosphere[see bottom of post]
1991 Gulf War veterans are suffering from 1991 Gulf War Illness[3;References]. Scientific research suggests the combination of experimental medication, pyridostigmine bromide as an example, over use of pesticides, chemical weapon-sarin as an example-destruction at plants and football sized bunkers, oil fires, etc as the potential cause[6-9].
Dr. Robert Haley, MD, UT SouthWestern Medical Center, and Intelligence Analyst James Tuite have reported how 1991 Gulf War veterans might have been contaminated with chemical weapons prior to the ground war, “Desert Storm”. In fact, their work provides data proving that sophisticated equipment detected chemical weapons in Saudi Arabia prior to the ground war[9a]. It is also hypothesized that the “toxic cocktail” has caused autonomic dysfunction, nerve death, and brain death[9-14].
As a 1991 Gulf War veteran, I have been affected. I am also a chemical engineer with a degree in biological sciences. Like most educated, I have lost much of my knowledge in chemical engineering and biological sciences, but I can, if I find a good example, still “plug and chug” by using “tested and trusted” equations, which is advised anyhow. 🙂 Here, I compare the diffusivity of sarin vapor and water vapor in air by using Chapman and Enskog equation with Brokaw relations for polar gases correction. I have shown that the equation can be used when considering the diffusivity of polar in a non-polar matrix. After performing the latter calculation, I noticed that reference  also suggests Brokaw relations to be used for diffusivity of one polar gas molecule in a non-polar matrix.
I will be comparing the diffusivity of polar sarin = A in non-polar air = B at 10C and 1 atmosphere. I chose 10C because I discovered data, possibly experimental, that stated that 90% volume of 1 mm sarin drop on a non-absorbable surface at 10C evaporated in 0.24 hours.
Chapman and Enskog Equation. Reference  reports that this equation has a “Average absolute error” of 7.9% when used without Brokaw relations. The range is from 0% to 25%. The authors did not provide an average for Browkaw relations but do provide specific absolute error values. When I averaged the Brokaw values, I obtained a 10.9% average absolute error with a range from 0% to 33%.
Chapman and Enskog Equation
Neufield, et al. Equation
Polar Gases: Brokaw Relations
When is chosen as unity and “n” is expressed by the ideal-gas law, the Chapman-Enskog Equation
Brokaw Diffusivity: Water in Air at 10C and 1 Atmosphere
Air: 1 mole basis
Note: I will only be calculating a delta value for water because air is non-polar[1;19].
Need to calculate
Neufield, et al.:
Water: 2.32 ; Air (Appendix B): 3.711
Diffusivity: Polar water in non-polar air at 10C and 1 atmosphere
Brokaw Diffusivity of Sarin in Air at 10C and 1 Atmosphere
Air: 1 mole basis
0.21 (1 mol) = 0.21 mol oxygen gas; 0.79 (1 mol) = 0.79 mol nitrogen gas
Note: I will only be calculating the delta value for the polar gas sarin because air is non-polar[1;19].
dipole moment, debyes
liquid molar volume at the normal boiling point,
normal boiling point (1 atm), K
Chapman-Enskog equation after polar correction
Diffusivity of Sarin in Air:
Diffusivity Comparison in Air: Water Versus Sarin in Descending Order
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