Molecular diffusion, often called simply diffusion, is the thermal motion of all ( liquid or gas ) particles at temperatures above absolute zero.

Molecular diffusion is typically described mathematically using Fick's laws of diffusion.

Molecular diffusion from a microscopic and macroscopic point of view.

** Molecular diffusivity ( often called " diffusion coefficient ")

Molecular diffusion | Diffusion is an example of the law of large numbers, applied to chemistry.

Molecular diffusion will slowly evolve the parcel properties.

* Molecular diffusion

# REDIRECT Molecular diffusion

* Molecular diffusion, spontaneous dispersion of mass ( distinct from migration, caused by an external force )

* Molecular diffusion

Molecular diffusion controls mixing of soluble organic compounds into groundwater and transport of oxygen from underlying groundwater or the capillary fringe of the groundwater surface to micro-organisms capable of catabolizing dissolved organic compounds remaining in the effluent plume.

* Molecular diffusion

Molecular diffusion in tissues is not free, but reflects interactions with many obstacles, such as macromolecules, fibers, membranes, etc.

* Chemistry: Molecular theory — Kinetic theory of gases — Molecular orbital theory — Valence bond theory — Transition state theory — RRKM theory — Chemical graph theory — Flory-Huggins solution theory — Marcus theory — Lewis theory ( successor to Brønsted – Lowry acid – base theory ) — HSAB theory — Debye – Hückel theory — Thermodynamic theory of polymer elasticity — Reptation theory — Polymer field theory — Møller – Plesset perturbation theory — Density Functional Theory — Frontier molecular orbital theory — Polyhedral skeletal electron pair theory — Baeyer strain theory — Quantum theory of atoms in molecules — Collision theory — Ligand field theory ( successor to Crystal field theory ) — Variational Transition State Theory — Benson group increment theory — Specific ion interaction theory

* Molecular sieve, a material containing tiny pores of a precise and uniform size that is used as an adsorbent for gases and liquids.

The features that make the diffusion pump attractive for high and ultra-high vacuum use are its high pumping speed for all gases and low cost per unit pumping speed when compared with other types of pump used in the same vacuum range.

The pumped gases continue flowing to the base of the pump at increased pressure, flowing out through the diffusion pump outlet, where they are compressed to ambient pressure by the secondary mechanical forepump and exhausted.

Transport of material in stagnant fluid or across streamlines of a fluid in a laminar flow occurs by molecular diffusion. Two adjacent compartments, separated by partition containing pure gases A or B may be envisaged.

If no bulk flow occurs in an element of length dx, the rates of diffusion of two gases A and B must be equal and opposite, that is.

The Chapman-Enskog formulas for diffusion in gases include exactly the same terms.

Today, Fick's Laws form the core of our understanding of diffusion in solids, liquids, and gases ( in the absence of bulk fluid motion in the latter two cases ).

‪ File: Boltzmann2. jpg ‬| Ludwig Boltzmann ( 1844-1906 ): developed statistical mechanics ( how the properties of atoms – mass, charge, and structure – determine the visible properties of matter, such as viscosity, thermal conductivity, and diffusion ), developed the kinetic theory of gases .‬‬‬‬‬

The capillaries are a single cell in diameter to aid fast and easy diffusion of gases, sugars and other nutrients to surrounding tissues.

The gas exchange tissues are set into the walls of the atria and gases travel via diffusion between the gas exchange tissues and the lumen of each parabronchus.

Often done with gases, but also with liquids, the diffusion method relies on the fact that in thermal equilibrium, two isotopes with the same energy will have different average velocities.

For dilute gases, kinetic molecular theory relates the diffusion coefficient D to the particle density n = N / V, the molecular mass M, the collision cross section, and the absolute temperature T by

Thomas Graham FRS ( 21 December 1805 – 16 September 1869 ) was a nineteenth-century Scottish chemist who is best-remembered today for his pioneering work in dialysis and the diffusion of gases.

# His studies on the diffusion of gases resulted in " Graham's Law ", which states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass.

The diffusion pathway is then reduced and gases can be transferred more easily.

Insects were once believed to exchange gases with the environment continuously by the simple diffusion of gases into the tracheal system.

In gases and liquids, conduction is due to the collisions and diffusion of the molecules during their random motion.

The coelom can be used for diffusion of gases and metabolites etc.

Graham's research on the diffusion of gases was triggered by his reading about the observation of German chemist Johann Döbereiner that hydrogen gas diffused out of a small crack in a glass bottle faster than the surrounding air diffused in to replace it.

Graham measured the rate of diffusion of gases through plaster plugs, through very fine tubes, and through small orifices.

Topics assigned to Gustav Hertz ’ s Institute G included: ( 1 ) Separation of isotopes by diffusion in a flow of inert gases, for which Gustav Hertz was the leader, ( 2 ) Development of a condensation pump, for which Justus Mühlenpfordt was the leader, ( 3 ) Design and build a mass spectrometer for determining the isotopic composition of uranium, for which Werner Schütze was the leader, ( 4 ) Development of frameless ( ceramic ) diffusion partitions for filters, for which Reinhold Reichmann was the leader, and ( 5 ) Development of a theory of stability and control of a diffusion cascade, for which Heinz Barwich was the leader ; Barwich had been deputy to Hertz at Siemens.

Dissolved gases are brought to cells and enter the cells via simple diffusion.