Write notes on diffusion of Gases.

Explanation

Diffusion : The property of gases to spread and occupy the available space is known as diffusion.
` to ` It is a non- directional phenomenon.
Effusion : The escape of a gas from high pressure region into space through a fine hole.is called effusion.
`to ` It is uni difectional phenomenon.
Rate of diffusion : No.of molecules diffused per unit time is called rate of diffusion.
Graham.s law of diffusion : At a given temperature and pressure, the rate of diffusion of a gas is inversely proportional to the square root of density, vapour density or molecular weight,
` r prop (1)/(sqrt(d)) ,r prop (1)/( sqrt(VD)) , r prop (1)/( sqrt(M ))`
If `r_1` and `r_2` are the rates of diffusion of two gases `d_1` and `d_2` are their densities respectively, then
` (r_1)/(r_2) = sqrt((d_2)/(d_1))`
This equation can be written as:
` (r_1)/(r_2) = sqrt((d_2)/(d_1)) = sqrt((VD_2)/(VD_1)) = sqrt((M_2)/(M_1))`
Comparison of the volumes of the gases that diffuse in the same time. Let `V_1` and `V_2` are the volumes of two gases that diffuse in the same time t.
` (r_1)/(r_2) = ((V_1)/(t_1))/((V_2)/(t_2))`
When time of flow is same then: ` (r_1)/(r_2) = (V_1)/(V_2)`
When volume is the same then : `(r_1)/(r_2) = (t_2)/(t_1)`
Applications :
`to ` This principle is used in the separation of isotopes like: `U^(235)` and `U^(238)`
` to ` Molar mass of unknown gas can be determined by comparing the rate of diffusion of a known gas molecular mass.
` to ` Ansil.s alarms which are used in coal mines to detect the explosive marsh gas works on the principle of diffusion.