Effusion was explained by a Scottish chemist named Thomas Graham. Thomas Graham found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles. The equations of Graham's law of effusion, is square root of the molar mass of gas one over the square root of the molar mass of gas two.
Diffusion is the effusion into a closed area of space. Diffusion is experimentally impossible to calculate with today's technology. We can, however, calculate the diffusion rate in a vacuum by using Graham's law of effusion. Using the ratio created by this equation we can calculate the distance between the two gases where they will meet.
The quantitative kinetic molecular model is used to derive the ideal gas law which explains how pressure multiplied by volume and divided by the constant .08206 multiplied by the temperature multiplied by the number of moles. The quantitative kinetic molecular model begins with velocity. First, we must find the collision frequency to do that you must divide the velocity in the x direction by the distance between the walls of the cube. Next, what is force? Force is mass multiplied by the change in velocity divided by the change in time. In this example there is no change in the magnitude of velocity. So, the change in velocity is final momentum minus initial momentum which equals negative two momentum. Since we know that you cannot have negative momentum and every action has an equal and opposite reaction we can confidently say that the impact on the wall is equal to - (-2mux). In saying that, we can state that force is equal to 2mux2 divided by L. Since we know that u2 = ux2 + uy2 + uz2 then 2mux2 divided by L + 2muy2 divided by L + 2muz2 divided by L is = to 2mu2 divided by L. To find pressure we need to calculate the force per unit of area. 2mu2 divided by L divided by 6L2 which is equal to mu2 divided by 3V this is the pressure of one molecule on the walls of the cube.
