How Does Temperature Affect the Rate of Diffusion?

The rate of diffusion of all types is increased along with increasing temperature. Diffusion is really the result of random movements, rather than force, since random movements are more likely to move particles to areas of lower concentration from areas of higher concentration. Temperature is a measure of the kinetic energy within particles, and hotter particles move faster, causing diffusion to proceed more quickly.

Temperature is an important factor in determining the rate of diffusion, but it is only one of several. Another aspect of diffusion rate, still related to temperature, is the size of the particles involved. A larger particle requires more energy to move, and therefore at any given temperature, larger particles tend to diffuse slower than smaller ones. The concentration difference is also another important factor, with greater differences resulting in faster diffusion.

While writings about diffusion often describe the process as the tendency of particles to move from areas of higher concentration to areas of lower concentration, this is somewhat misleading. There is no force in normal diffusion that makes any particular particle more likely to move into an area of lower concentration. This tendency of diffusion is merely a matter of odds, as particles are more likely to move from higher concentration to lower concentration than the opposite simply because there are more particles in high concentration areas to move elsewhere.