Molecular diffusion

Thermal motion of liquid or gas particles at temperatures above absolute zero

Molecular diffusion is the motion of atoms, molecules, or other particles of a gas or liquid at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid, size and density (or their product, mass) of the particles. This type of diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration.

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