The discussion revolves around the relationship between the size of gas molecules and the volume they occupy at standard temperature and pressure (STP), specifically addressing the ideal gas law and the approximation of 22.4 liters per mole for gases. Participants explore the implications of molecular size on gas behavior and volume occupancy.
Participants generally agree that the 22.4 L volume is an approximation and that real gases do not behave ideally, but there is no consensus on the implications of molecular size on gas volume occupancy.
The discussion highlights assumptions about ideal gas behavior and the limitations of the 22.4 L approximation, particularly in relation to real gases and their deviations from ideality.
Readers interested in gas laws, thermodynamics, and the behavior of gases under varying conditions may find this discussion relevant.
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.