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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: AdiDex on September 25, 2015, 10:49:19 AM

Title: Real gases
Post by: AdiDex on September 25, 2015, 10:49:19 AM

I am very badly confused with compressibilty graph of real gases ??

If it has value greater than 1 , It means they will occupies a larger volume than they should occupy according to ideal gas law ??
Why at high pressure they have value greater than 1 ? is this because due to repulsion ?? Some of the gases even have slope always positive such as He and N₂  that means they changes their volume rapidly..!! why it is so ??

Can anybody answer ?? Or refer any book in which I can find my answers...!!

Title: Re: Real gases
Post by: Corribus on September 25, 2015, 11:08:45 AM

Maybe this post (and thread) will help.

http://www.chemicalforums.com/index.php?topic=72293.msg261720#msg261720

Title: Re: Real gases
Post by: Enthalpy on September 27, 2015, 07:21:11 PM

A compressibiilty factor >1 means that the real gas takes more volume than the ideal gas law would predict. The usual reason is the volume of the molecules, which the ideal gas law neglects. This volume is a correction in Van der Waals' law for instance, and uses to be a bit less than the liquid's volume.

Nice post there, Corribus!