For example, for a 12'x25' single-car driveway with a 9 bed of gravel (in three layers), convert 9 to 0.75'; multiply 0.75 x 12 x 25, which equals 8.34 cubic yards, or roughly 10-14 tons. A 4 layer of gravel to resurface an existing 12'x25' driveway requires about 2.78 cubic yards or roughly 3.33-4.73 tons.
Diffusion [edit]. Diffusion of KMnO4 in water. Diffusion is the process of a substance spreading out to evenly fill its container or environment. In a solution, a concentrated solute diffuses to spread evenly in its solvent. In air, gas molecules diffuse to mix thoroughly. Substances diffuse from areas of high concentration to low concentration.
Diffusion is the net movement of molecules or atoms from a region of high concentration to a region of low concentration.n the phenomenological approach, diffusion is the movement of a substance from a region of high concentration to a region of low concentration without bulk motion. According to Fick's laws, the diffusion flux is proportional to the negative gradient of concentrations.