### Graham’s diffusion law

Lighter molecules move faster than the heavier one. According to this concept Graham’s could reach his law ,but at first we should to differentiate between to terms Diffusion and Effusion).

Diffusion: **process resulting from random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration**.

Effusion: is escape of a gas through a pinhole without molecular collisions.

Graham’s law of diffusion: under the same conditions of temperature and pressure, the rates of diffusion of different gases are inversely proportional to the square roots of their molecular masses.

From the previuos law we can conclude that:

R_1 = \sqrt{\frac{1}{M.wt_1}}

R_2 = \sqrt{\frac{1}{M.wt_2}}

By dividing 1over 2:

\frac{R_1}{R_2} = \sqrt{\frac{M.wt_2}{M.wt_1}}

If we are taking about effusion then:

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