Answer to Question #23854 in Physical Chemistry for Aanal
Why does the graph of rate of effusion versus time exponentially decrease with pressure?
The rate of effusion of a gas is inversely proportional to the square root of the mass of its particles. In other words, the relative rates of effusion of two gases at the same temperature and pressure are given by the inverse ratio of the square roots of the masses of the gas particles. RMS speed of molecules is √3RT/M,so rate of effusion is inversely proportional to square root of molar mass. RMS speed = √PV/M, so rate of effusion should be proportional to square root of pressure, so its not exponential dependence.