Concentration Gibbs energy

Furthermore, equilibria hold for ions and electrons. In every case, the Gibbs energy of the defect reaction has to provide a minimum for the equilibrium concentrations ... 

During ATP synthesis, protons move down these gradients from outside [Hour] into the mitochondrial matrix each proton doing both electrical and osmotic work (due to the concentration difference) so that the Gibbs energy change is... 

The concentration of this species in liquid sulfur was estimated from the calculated Gibbs energy of formation as ca. 1% of all Ss species at the boihng point [35]. In this context it is interesting to note that the structurally related homocyclic sulfur oxide Sy=0 is known as a pure compound and has been characterized by X-ray crystallography and vibrational spectroscopy [48, 49]. Similarly, branched long chains of the type -S-S-S(=S)-S-S- must be components of the polymeric S o present in liquid sulfur at higher temperatures since the model compound H-S-S-S(=S)-S-S-H was calculated to be by only 53 kJ mol less stable at the G3X(MP2) level than the unbranched helical isomer of HySs [35]. 

Solntions in which the concentration dependence of chemical potential obeys Eq. (3.6), as in the case of ideal gases, have been called ideal solutions. In nonideal solntions (or in other systems of variable composition) the concentration dependence of chemical potential is more complicated. In phases of variable composition, the valnes of the Gibbs energy are determined by the eqnation... 

The method of calculating these values was proposed by R. A. Robinson and R. H. Stokes. The Gibbs energy G of a system containing 1 mole of uni-univalent electrolyte ( t = 1, total number of moles of ions being 2) and n0 moles of solvent is expressed for solvated ions (dashed quantities) on one hand and for non-solvated ions (without dash) on the other it is assumed that jU0 = jUo and that the hydration number h (number of moles of the solvent bound to 1 mole of the electrolyte) is independent of concentration ... 

Using the concentrations and pressures provided we can calculate the Gibbs energy for the combustion of glucose under biological conditions. First, we need to replace the activities by the appropriate effective concentrations. That is,... 

The output of a battery depends upon the concentrations and Gibbs energy of the components at the anode and cathode. Because of this, battery technology also underpins the operation of many sensors. 

Since the absolute and the conventional electrode potentials differ only by an additive constant, the absolute potential depends on the concentration of the reactants through the familiar Nernst s equation. This dependence is implicitly contained in Eq. (2.6) the real Gibbs energies of solvation contain an entropic term, which depends on the concentration of the species in the solution. 

The difference between the potential of the current peak for the desorption and the bulk deposition potential is known as the underpotential shift simple systems the value of Gibbs energies of adsorption and deposition shift both according to the Nernst equation. Deviations from this behavior may indicate coadsorption of other ions. 

All quantities in Eq. (12.6) are measurable The concentrations can be determined by titration, and the combination of chemical potentials in the exponent is the standard Gibbs energy of transfer of the salt, which is measurable, just like the mean ionic activity coefficients, because they refer to an uncharged species. In contrast, the difference in the inner potential is not measurable, and neither are the individual ionic chemical potentials and activity coefficients that appear on the right-hand side of Eq. (12.3). 

It is apparent that the deviation from Nemstian behaviour depends on the activity of the determinand and anion B in the studied solution. It decreases with increasing magnitude of the sum of the standard Gibbs energies of transfer of ions J and B " from water into the membrane phase. The effect of the interfering anion is suppressed by increasing the concentration of the ion-exchanger ion in the membrane. 

This chapter will begin, very briefly, with the thermodynamic representation of Gibbs energy for stoichiometric compounds before concentrating on the situation when mixing occurs in a phase. 

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