Electrochemical potential of ion

According to Ershler, 0X must appear in the expression for the electrochemical potential of ions adsorbed on the inner Helmholtz plane. If their electrochemical potential is expressed by the equation... 

C-1/3 is the average separation distance between the ions whereas (Co)-1 3 characterizes the range of rigid interaction.) The electrochemical potential of ions, modified by ip, assumes the form (compare with (1.19b))... 

Let us now consider the reaction of acetic acid dissociation shown in Eq. 8.37. By using the electrochemical potential of ions, the equilibrium of the reaction is expressed in Eq. 8.42 ... 

The chemical and electrochemical composition of the extracellular medium is essentially different from the intracellular medium. Equilibrium is achieved when the electrochemical potential of ions is the same on the inside and outside, and is expressed by... 

As described in Chapter 13, electrochemical potential is an effective means of storing free energy. Indeed, the electrochemical potential of ion gradients... 

The term [dG/dni f p , i the chemical potential (p ). The electrochemical potential, often denoted as ft , is the corresponding quantity for a system containing ionic charges, where the energy state of one ion depends on both chemical and electrical interactions with solvent molecules and other ions in the system. Guggenheim [5] separated the electrochemical potential of ion species i in phase a into chemical and electrical components ... 

The equilibrium in a system where phases in contact bear different electric potentials, (p, is determined by the condition of the equal electrochemical potentials of ions. The electrochemical potentials of ions of /-th kind, I are related to their chemical potentials, p,, via the following relationship ... 

At equilibrium, electrochemical potentials of ions are constant over the diffuse layer and these relations hold within the DL ... 

As there is no analogue of Butler s equation for ionised surface layers, the procedure used to derive the equation of state has to be based on the Gibbs adsorption equation and a model adsorption isotherm. The isotherm equation can also be derived from the theoretical analysis of the expressions for electrochemical potentials of ions. For the solution of a single ionic surfactant RX, with the addition of inorganic electrolyte XY, starting from Eqs. (2.2) and (2.21) for the electrochemical potentials, one obtains the adsorption isotherm... 

Fixed Charge Theory. As a result of combining the above two theories, a fixed charge membrane theory was developed by Teorell and Meyer and Sievers. The theory includes the equilibrium of the electrochemical potentials of ions at the membrane boundaries and the diffusion of ions in the membrane. Therefore, the total membrane potential E is composed of three separate potential differences Eo corresponds to the first transition region between the solution (o) and membrane phases, difl corresponds to the ion diffusion potential in the membrane, and corresponds to the other transition region between membrane and the solution (i) phases (see Figure 26B). Thus, the transmembrane potential is... 

Under steady-state conditions the partial currents persist, so that // = const., and Eq. (88) is then a first-order nonlinear differential equation containing unknown functions q and E and unknown constant U This fundamental electrodiffusion equation, conventionally referred to as the Nernst-Planck equation, may be obtained by direct differentiation of the expression for the electrochemical potential of ion species / present in the dilute solution... 

However the electrochemical potential of Ions can be divided into two terms, one called purely electric and the other called chemicalpotential. This is because the latter term shares the same form as that of the equations seen above ... 

When selective voltage probes are used which can exchange orfly electrons or only ions, the net current vanishes (provided a high-impedance voltmeter is used). However, this is a dynamic equilibrium where the mobile species are transported across the probe/sample interface with a net zero flux. The probes, then, are used to transfer information, namely, the electrochemical potential of ions or electrons. 

Charging processes at membranes, demanded by the constancy of the electrochemical potential of ions that can pass through, are the basis of elec-trophysiological processes and are of paramount importance in nerve signal propagation. 

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