Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Mean Free Path: Physics Question?
Calculate the mean free path of air molecules at a pressure of 5.00×10−13 atm and a temperature of 292 K .
(This pressure is readily attainable in the laboratory.)
Model the air molecules as spheres with a radius of 2.00×10−10 m.
Any help would be greatly appreciated.
Thank you in advance
1 Answer
- hfshawLv 73 years agoFavorite Answer
The mean free path of molecules in a gas a a temperature T and pressure p is given by:
λ = R*T/[sqrt(2)*π*d²*N*p]
where R is the universal gas constant, d is the effective diameter of the molecules, and N is Avogadro's number. [derivation given in source]
In this case,
λ = (8.206*10^(-5) m³*atm/(mol*K))*(292 K)/[sqrt(2)*π*(4.00*10^(-10)m)²*(6.022*10^23/mol)*(5.00*10^(-13) atm)]
λ = 1.12*10^5 meters = 112 km = 69.6 mi (to the appropriate number of significant figures)
