Ideal Gas Law: Encyclopaedic Experimental Data

[Prokop]

The “ideal gas” law

The well-known, encyclopaedic experimental data (about gas compressability factor) show the general trend:
the more rarefied gas the more accurate “ideal gas” law,
or the same in other terms:
the higher vacuum the more accurate “ideal gas” law.
1) Are another experimental data which contradict the trend ?
2) Are the theory which explains the trend ? (Classic or quantum molecular-kinetic theories do not considered as absolutely unsuitable).
3) Does your conclude the so called “ideal gas” is namely vacuum ?

 

[Nick89]

I'm not sure if I understand your questions correctly, but I'll have a go at answering them:

1) I don't know but I don't think so.

2) The ideal gas law is a law derived from statistical mechanics. It treats the gas molecules as point particles, with no volume. It also assumes the particles do not 'feel' each other in any way except that they bounce elastically with each other and the walls.

Now imagine if you have a LOT of particles, they will take up a lot of space. But in the ideal gas law model, they won't take up any space at all since they are all point particles! Clearly the law will not work very well there.
If you have very little particles however, the little volume they take up will not be so important and the ideal gas law will work much better.

3) An ideal gas is not a vacuum, since a (perfect) vacuum means actually no gas at all (this cannot exist in reality). An ideal gas does not exist, it is merely a theoretical model of a gas.