At standard temperature and pressure (STP), every gas occupies a volume of 22.4 liters per mole, regardless of molecular size. This is based on the ideal gas law, which assumes that gas molecules are far apart and that their size is negligible compared to the total volume. The pressure of a gas at STP is determined by the average kinetic energy of the molecules and their concentration, which remains constant and independent of molecular weight. While the 22.4 L per mole is an approximation, real gases deviate slightly from this ideal behavior.
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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.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
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.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.
Right. Real gasses are not quite ideal.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.
Thank you so much this doubt was not letting me study for my exams.jbriggs444 said:Right. Real gasses are not quite ideal.