How Does the Ideal Gas Theory Account for Volume and Mass?

[wanderlust44]

This might be a stupid question, but I am confused about the ideal gas theory. I know that we assume high temperatures and low pressures, and that the volume is negligible when we compare it to a container, but my textbook is very confusing about this point.

It says assume zero/negligible volume and mass, but then goes on to calculate 1 mol of any gas at STP is 22.4L. Also, it says that the conditions of ideal gas do assume that there is no volume or IMF, but that it would have some mass. How can it have no volume and a 22.4L volume (and no mass)? I think I need clarification with regards to what it is talking about. Is it talking about the particles?

Also, if we look at the graph of pressure and temperature, wouldn't negligible volume mean 0K rather than 273.15K? Thanks for the clarification.

 

[lisab]

Could the text be saying, assume zero/negligible *change* in mass and volume?

 

[SteamKing]

It would be better for us to provide direct quotes from your text on this point. All we are doing now is playing a game of Telephone.

 

[Yanick]

No volume refers to the volume taken up by a specific atom of gas, not the bulk gas as a whole. The 22.4L of 1mol at 1bar pressure is only an approximation and does not hold for real gases, in reality the small/light monatomic gases are close to 22.4L but not exactly there. The discrepancy lies in the fact that each particle of gas does in fact take up some volume and that there are slight intermolecular forces.