Question

Distinguish between diffusion and effusion.

Answer 1

Difference Between Effusion and Diffusion

Effusion	Diffusion
Effusion is said to occur when gas molecules escape through a pinhole into a vacuum.	During diffusion one gas mixes with another usually by thermal random motion resulting in the collision between each other while releasing molecular energy.
Effusion in simple terms is the ability of gas to travel through a small opening.	Diffusion is the ability of gases to mix with each other usually in the absence of a barrier.
Effusion occurs when the size or aperture of the hole is smaller than the mean free path of the molecules.	Diffusion happens when there are no holes or if holes in the barrier are larger than the mean free path.
Effusion occurs or is facilitated by a difference of pressures.	Diffusion occurs due to difference in concentrations.