Racing, moving to the next level Options

[Randal]

OK, all you big time racers out there, what is the correct procedure to purge air out of a tire before filling it with nitrogen?

The reason I ask is that any moisture mixed with nitrogen will create nitric acid, or some such vile stuff, if I remember correctly.

What about using air tools? Looks like a job for rubber gloves.

[MattR]

well from a beginning level of chemistry I can tell you;

PV=nRT

that is the Pressure times Volume equals number of moles (or molecules) in the gas times a constant times the temperature.

It would make logical sense that, assuming n, R, and V are going to stay the same (because no air escapes and volume doesnt change), as temperature increases, pressure increases. To combat that, you would have to decrease the number of molecules in the gas (a property of the gas) to make the pressure less sensitive to temperature. I dont have any values on me, and this problem would be very complex because n of ambient air varies a lot, but I can say the atomic mass of oxygen is 16 and nitrogen is 14. Now if you were to go to hydrogen or something (atomic mass of 1) there might be a noticable difference, but I think 2 molecules would be considered neglegable.

But what do I know...