Molecule Size VS Occupied Volume of Gases

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Karan Punjabi
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Ar STP Every gas occupies same volume of 22.4 L but how it can be because every gas molecule has different size right? So they should occupy different volumes right? If I'm wrong at any point then please correct me
 
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Karan Punjabi said:
Ar STP Every gas occupies same volume of 22.4 L but how it can be because every gas molecule has different size right? So they should occupy different volumes right? If I'm wrong at any point then please correct me
In an ideal gas, the molecules are far apart. The size of molecules is a small fraction of the total volume. That is the assumption that goes into the 22.4 liters per mole approximation. In a diffuse gas, pressure is a function of the average kinetic energy of each molecule and the concentration of molecules. At STP and one mole per 22.4 liters, the average kinetic energy and the concentration of molecules is fixed and does not depend on molecular weight. Accordingly, the pressure is fixed and does not depend on molecular weight.
 
jbriggs444 said:
In an ideal gas, the molecules are far apart. The size of molecules is a small fraction of the total volume. That is the assumption that goes into the 22.4 liters per mole approximation. In a diffuse gas, pressure is a function of the average kinetic energy of each molecule and the concentration of molecules. At STP and one mole per 22.4 liters, the average kinetic energy and the concentration of molecules is fixed and does not depend on molecular weight. Accordingly, the pressure is fixed and does not depend on molecular weight.
So that's just a approximation that volume is 22.4 L but in practical the volume vary little bit right ? I know that kinetic energy is fixed for any gas at a given constant temperature.
 
Karan Punjabi said:
So that's just a approximation that volume is 22.4 L but in practical the volume vary little bit right ? I know that kinetic energy is fixed for any gas at a given constant temperature.
Right. Real gasses are not quite ideal.
 
jbriggs444 said:
Right. Real gasses are not quite ideal.
Thank you so much this doubt was not letting me study for my exams.