On Sat, 10 Dec 2016 13:49:31 -0800 Greg Fiorentino via Mercedes <mercedes@okiebenz.com> wrote:
> Yes, but > > <<...the electrostatic interaction between the electron clouds of the > colliding molecules is repulsive.>> > > ;-) Yes, that is true. Everything we sense about materials in our every day interactions with them is because of their atoms' electron clouds. We never experience their nuclei. So when you are standing on the 12th floor, keep in mind that the only thing holding you up is electron repulsion ... > Interesting that the O2 molecule is smaller despite having a greater > molecular weight. I was wondering if the O atom has electrons at a > higher energy level than the N atom, but I see that it would take 9 > electrons to exceed the s and p orbitals. So, perhaps the same electron > orbital energy levels plus the higher proton count in the nucleus gives > a smaller atom due to proton-electron attraction. That's what the article says. > Thanks Craig! You are welcome. > -----Original Message----- > From: Mercedes [mailto:mercedes-boun...@okiebenz.com] On Behalf Of > Craig via Mercedes > Sent: Saturday, December 10, 2016 1:07 PM > To: Mercedes Discussion List > Cc: Craig > Subject: Re: [MBZ] OT: Nitrogen vs Air for tires > > On Fri, 9 Dec 2016 11:51:47 -0600 OK Don via Mercedes > <mercedes@okiebenz.com> wrote: > > > But I don't remember Boyles law being different for different gases. > > Are the thermal expansion coefficients different for N and O? > > Nope. PV = nRT, with R being the same for all gases, > > 8.3144598(48) J > ----------------- > mol K > > Part of your email references humidity -- I'm not sure of the effect of > that. If the tire is filled with humid air, the moisture could condense > on the inside of the tire as the temperature drops, particularly below > freezing. Changing water from vapor to liquid will decrease its volume > and lower the total pressure. > > Air also contains oxygen which could help degrade the rubber, though the > outside of the tire always has oxygen surrounding it and is subjected to > sunlight with its consequent ultraviolet. > > The attached paper discusses the permeation of nitrogen and oxygen > through tire rubber. It says that oxygen, having a smaller molecular > diameter than nitrogen, permeates tire rubber 3.33 times faster than > does nitrogen. Thus, nitrogen is to be preferred to air because the > tire pressure will not leak down as rapidly. > > It does not, however, mention anything about temperature. > > > Craig _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
