Graham's Law of Effusion / Diffusion
Diffusion:
Then inter mixing of particles of matter is called Diffusion.
In solids the particles are rigidly packed that, it is impossible for the solid to diffuse easily.
In liquid, the diffusion is possible because there is moderate inter-molecular force of attraction and moderate inter-molecular space between the particles. So, the diffusion is possible.
In gases, the particles possess very less inter-molecular force of attraction, that is, the particle are almost independent of each other. So the diffusion is highly possible in gas
Effusion:
Effusion is also related with Diffusion.
The escaping of the particle of gases through a a tiny hole is called Effusion.
Using the Graham law of effusion / Diffusion, we are just going to find the rate of effusion or diffusion of gases.
Graham's Law of Effusion / Diffusion:
Grahams law of effusion states that the rate of the effusion of a gas is inversely proportional to the square root of its molar mass.
Graham's Law
Rate of effusion ∝ 1 / √(molar mass)
Ratio of rate of effusion:
Gas 1: Rate of effusion(no.1)[R₁] ∝ 1 / √(molar mass )(no.1)[M₁]
Gas 2: Rate of effusion (no.2)[R₂]∝ 1 / √(molar mass)(no.2)[M₂]
R₁ /R₂ =√(M₂/M₁)
Problems related to Rate of Effusion and Diffusion:
Q: Ammonia has a molar mass of 17.0 g/mol; hydrogen chloride has a molar mass of 36.5 g/mol. What is the ratio of their diffusion rate?
A:
R₁ is rate of diffusion of Ammonia, it is molar mass (M₁) is 17 g/mol
R₂ is rate of diffusion of hydrogen chloride, it's molar mass (M₂) is 36.5 g/mol
R₁/R₂ = √(M₂/M₁)
R₁/R₂ = √(36.5/17)
R₁/R₂ = √2.14
R₁/R₂ = 1.46
So the ratio of rate of diffusion(ammonia: hydrogen chloride) is 1.46
So the ratio of rate of diffusion(ammonia: hydrogen chloride) is 1.46
