Question

How is the movement of particles in diffusion determined?

Answer 1

Diffusion is driven by the concentration gradient and kinetic energy of the particles/molecules that move in random motion and collide with one another. Diffusion is the movement of particles/molecules from an area of high concentration to an area of low concentration. Diffusion process continues until the particles/molecules are evenly distributed in the whole available space.

Answer 2

Diffusion is a net movement of particles through a barrier driven by a concentration gradient. In diffusion, particles move from an area of higher concentration to the area of lower concentration in order to balance concentrations on the both sides of the barrier. For example, when you put a teabag into a hot water, concentration of tea particles in the hot water is much lower than in a teabag and the particles of tea will diffuse into water.