Forum menu
[quote=jonba ]N2 is larger than CO2 300pm comapred to 232 according to wikipedia. Not sure if that will be the most substantial contributing factor to diffusion through a tyre?
It might not be - you could always read the thread for other suggestions...
When kwikfit put nitrogen in your f1 tyres... there’s already a whole tyres worth of air in there (presuming your local branch doesn’t operate in a vacuum)*. So the tyres still won’t only have nitrogen in them, they’ll just have had nitrogen added to the air that was already there.
*a moral vacuum maybe
If it's the oxygen that leaks out, and the nitrogen that stays put in a car tyre when it goes down a bit, surely after a year or so it would be pretty much all nitrogen that's left anyway.
A bit like heavy water (Deuterium & Oxygen) being left in the bottom of an old kettle.
It's worse than that - if you get a pure nitrogen fill, the oxygen sneakily leaks back in.
Not sure if that will be the most substantial contributing factor to diffusion through a tyre?
It's worse than that
From a pedantic point of view it can't get much worse. You get OSMOSIS through a semi-permeable membrane (such as a tyre). Not diffusion.
Nitrogen cartridges are available that fit CO2 inflators too, they're controlled though because of the yoof.
That's N2O, you can get if from any catering supplier, it's only controlled in the same way as glue and paint thinner.
From the .gov site [i]"Retailers should pay particular attention to the potential for abuse of nitrous oxide, especially where customers seek to buy in bulk or large volumes."
[/i]
It's useless as a tyre inflator because unlike CO2 it won't liquefy at the right temperature and pressure.
I can't be bothered to look it up but under what conditions does Co2 liquefy. My only experience is using it as a gas or solid. Tends to sublime under atmospheric conditions.
It liquefies above atmospheric pressure. But yes, if you cool it at atmospheric pressure it solidifies first. Someone was talking about it's critical point earlier in the thread, which is slightly different, that's the point at which the latent heat of vapourisation reaches zero, so it forms a supercritical fluid, neither gas nor liquid (viscosity of a gas, density of a liquid).
It's triple point is -56C and 5bar (below that the gas will turn solid as you compress it or cool it at below that pressure)
It's critical point temperature is 31C (above that you cannot condense it into either a liquid or obviously a solid).
From a pedantic point of view it can't get much worse. You get OSMOSIS through a semi-permeable membrane (such as a tyre). Not diffusion.
No, if your being pedantic you get diffusion by osmosis (the oxygen diffuses through the rubber with the osmotic potential due to the difference in partial pressures). Osmosis just describes diffusion through a solid where the driver is partial pressure or concentration rather than absolute pressure.
Wouldn't CO2 have a greater dipole moment
Neither N2 or CO2 have a dipole moment.
Well if we are getting really picky, if you get yer CO2 molecule bending, it will have temporary dipoles, if you get it bending in two planes at once, it will look like a rotating dipole. Don't get that with N2 or O2.
wobbliscott
Puddles drying must be an unsolved mystery......
shermer75 - Member
I've always wanted it to be heliumPOSTED 4 DAYS AGO # REPORT-POST
Me too.
I knew I was being led into a seemingly "easy read" thread that would divert into quantum mechanics or similar at some point! 😀