Electro-Conductivity and Charge Transfer

In conclusion, it should be noted that transfer of mass is also possible due to a temperature gradient (Soret effect). 

The proportionality factor o , as well as the heat onductivity coefficient and diffusion coefficient, is a transport factor and is called mobility, since it characterizes the ability of charged particle to move in the medium under action of driving force (in this case - the electric field). This coefficient can be interpreted as average velocity of motion of charged particle in solution under action of a force equal to 1 N/mole. The dimensionality of u is N -m-s -mole. 

The concept of mobility, which we shall frequently encounter with further, is a generalized concept, because the mobility characterizes the particle s capacity of drift in liquid under action of any force (electric, magnetic, gravitational, centrifugal, etc.). 

Together with molar flux (4.32), we can also introduce the mass flux 

The mole flux is commonly used in research of electrochemical processes. 

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