what are the factors affecting rate …

Temperature :. Increasing the temperature increases the diffusion rate by adding energy to each particle. This is because particles with more energy bounce against each other more frequently and spread evenly throughout the material volume. Similarly, lowering the temperature will lower the diffusion rate by lowering the energy of each particle.

Concentration Difference: The rate of diffusion depends on the difference between concentrations across the host material, with higher concentration differences resulting in higher diffusion rates.

For example, diffusion through a thin wall or membrane will occur quickly if there is a high concentration of the gas on one side and none of the gas on the other side of the wall. If there is already an almost equal amount of gas on both sides, diffusion will be much slower.

Diffusion Distance: The rate of diffusion is inversely related to the distance through which the material is diffusing. That is, smaller distances result in faster diffusion rates and larger distances result in slower diffusion rates. This makes sense, since a gas diffuses through a thin wall much faster than it would diffuse through a thick wall.

Diffusing and Host Materials: Diffusion rate also depends on both the material that is diffusing and the material it is diffusing through. At a certain temperature, all particles have the same average energy. This means that lighter atoms, such as hydrogen, carbon, oxygen and nitrogen travel faster and are more mobile than larger atoms such as copper or iron. Materials made of these lighter atoms diffuse faster than heavier materials.