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The diffusion coefficient in solids at different temperatures is generally found to be well predicted by the Arrhenius equation: = where D is the diffusion coefficient (in m 2 /s), D 0 is the maximal diffusion coefficient (at infinite temperature; in m 2 /s),
In physical chemistry, the Arrhenius equation is a formula for the temperature dependence of reaction rates.The equation was proposed by Svante Arrhenius in 1889, based on the work of Dutch chemist Jacobus Henricus van 't Hoff who had noted in 1884 that the van 't Hoff equation for the temperature dependence of equilibrium constants suggests such a formula for the rates of both forward and ...
In dilute aqueous solutions the diffusion coefficients of most ions are similar and have values that at room temperature are in the range of (0.6–2) × 10 −9 m 2 /s. For biological molecules the diffusion coefficients normally range from 10 −10 to 10 −11 m 2 /s.
The self-diffusion coefficient of water has been experimentally determined with high accuracy and thus serves often as a reference value for measurements on other liquids. The self-diffusion coefficient of neat water is: 2.299·10 −9 m 2 ·s −1 at 25 °C and 1.261·10 −9 m 2 ·s −1 at 4 °C. [2]
The Fourier law states that heat energy flow has the following linear dependence on the temperature ... D is the diffusion coefficient that controls the speed ...
The diffusion coefficient ... describes thermodiffusion, the diffusion flux caused by the temperature ... Dependence on a total concentration n for a given ...
The diffusion coefficient can be combined with the reaction equilibrium constant to get the final form of the equation, where is the permeability of the membrane. The relationship being P = K D {\displaystyle P=KD}
The Kirkendall effect is the motion of the interface between two metals that occurs due to the difference in diffusion rates of the metal atoms. The effect can be observed, for example, by placing insoluble markers at the interface between a pure metal and an alloy containing that metal, and heating to a temperature where atomic diffusion is reasonable for the given timescale; the boundary ...