How would I calculate the speed of a particle in vacuum at, say 10-6 torr at room temperature?
Answer A particle (gas atom or molecule) of given mass (at a given temperature) will be somewhere on its Maxwell-Boltzmann velocity distribution curve for that temperature. There are a variety of velocity “averages” one can calculate: 1. most probably velocity given by 12,895 x (T/M)0.5 cm.sec-1 2. arithmetical average velocity given by 14,551 x (T/M)0.5 cm.sec-1 3. root-mean-square velocity given by 15,794 x (T/M)0.5 cm.sec-1 Note that the pressure is not a consideration in the distribution function. At a fixed temperature, it doesn’t matter if you are discussing 10-6 torr or atmospheric pressure, the velocity distribution is the same. Follow-up Question I originally asked the “speed of molecules in vacuum” question because someone here was suggesting that gravity had a major effect in vacuum (ie pumps on top of the system would be less efficient than on the bottom). I was hoping to use the speed of the molecules to show that gravity is not an issue. Can you give a simple explanation
