Actual Distance Between Atoms of an Ideal Gas

1. Sep 19, 2004

hawflakes

Hi, I am working on a project in which I need to know the distance between the particles in an ideal gas system. I have tried searching (google) for it but was unable to come with any actual values, just general terms. Can anyone refer me to where I might find this? Thanks

2. Sep 19, 2004

Gokul43201

Staff Emeritus
1 mole of a gas has ~ 10^24 molecules and occupies about 22 liters (or 22 dm^3) at STP. So, the average spacing between molecules is roughly the cube root of 22*10^-24 dm ~ 3*10^-8 dm = 3*10^-9 m or about 30 angstroms or 3 nm.

Note : This distance is a function of temperature. Use the Ideal Gas Law to figure out for other P,T values.

The mean free path calculator here also gives average intermolecular spacing.
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/menfre.html#c3

I know that Nitrogen deviates little from ideality over a fair range of temperatures and pressures...so here goes (now using this calculator, to double check):

At 760mm Hg, 273 K and molecular diameter of 2.0 A (2.0 * 10^-10 m), which is the diameter of a N2 molecule, the calculator gives 3.3 nm...close enough to my guess.

Last edited: Sep 19, 2004
3. Sep 19, 2004

Thank you!