Principle of electroneutrality

In a complex such as the sulfate ion the sulfuiMjxygen bond assumes multiple-bond character through resonance involving one sigma bond and two pi bonds. An empirical equation has been formulated connecting interatomic distances and bond number for resonance of this sort. On application of this equation it is found that in many complexes the amounts of multiple-bond character are such as to cause all atoms to conform rather closely to the principle of electroneutrality. 

The above statements are valid for monomolecular layers only. In the case of polymer films with layer thickness into the p-range, as are usually produced by electropolymerization, account must also be taken of the fact that the charge transport is dependent on both the electron exchange reactions between neighbouring oxidized and reduced sites and the flux of counterions in keeping with the principle of electroneutrality Although the molecular mechanisms of these processes... 

The principle of electroneutrality requires that the ionic species in an electrolyte solution remain charge balanced on a macroscopic scale. The requirement of elec-... 

Earlier, Gavach et al. studied the superselectivity of Nafion 125 sulfonate membranes in contact with aqueous NaCl solutions using the methods of zero-current membrane potential, electrolyte desorption kinetics into pure water, co-ion and counterion selfdiffusion fluxes, co-ion fluxes under a constant current, and membrane electrical conductance. Superselectivity refers to a condition where anion transport is very small relative to cation transport. The exclusion of the anions in these systems is much greater than that as predicted by simple Donnan equilibrium theory that involves the equality of chemical potentials of cations and anions across the membrane—electrolyte interface as well as the principle of electroneutrality. The results showed the importance of membrane swelling there is a loss of superselectivity, in that there is a decrease in the counterion/co-ion mobility, with greater swelling. 

A critical problem related to this is predicting the relative charge displacements which arise on coordination to a series of metal ions or of one metal ion in a series of different coordination environments. In this latter case there is a guide given by Nyholm 26) which is a corollary of Pauling s principle of electroneutrality. 

The first rule is the Principle of electroneutrality (Rule 11.1) which restricts the chemical composition of inorganic compounds to those in which the net charge is zero. In the context of the bond valence model this rule can be stated as ... 

Rule 11.1 (Principle of electroneutrality). Since the sum of all atomic valences is zero, the sum of the atomic valences of the cations is equal to the sum of the atomic... 

This amount of double-bond character is to be expected from consideration of the principle of electroneutrality (Sec. 8-2). The 30 percent partial ionic character of the Si—Cl bond that corresponds to the difference in electronegativity of the atoms would place the charge + 1.2 on the silicon atom in the SiCU molecule. This electric charge would be reduced to zero if each bond had 30 per cent double-bond character, or to +0.2 (a value approximating electroneutrality) if each bond had 25 percent double-bond character. This amount of doublebond character (and the same amount of partial ionic character for each bond) is given by resonance among the six equivalent structures of type B ... 

It appears from this argument that an electrolytic solution would sustain only a transient migration of ions and then the tendency to conform to the principle of electroneutrality would result in a halt in the drift of ions after a short time. A persistent flow of charge, an electric current, appears to be impossible, hi practice, however, an electrolytic solution can act as a conductor of electricity and is able to pass a current, i.e., maintain a continuous flow of ions. Is there a paradox here ... 

The principle of electroneutrality demands that the concentration of both positive and negative ions in the left-hand compartment be the same. Therefore,... 

Fig. 4.82. According to the principle of electroneutrality as applied to the fluxes, the flux of positive Ions Into a volume element must be equal to the flux of negative ions into the volume element, so that the total negative charge is equal to the total positive charge.

Fig. 5.23. The principle of electroneutrality is satisfied if the number of tagged positive ions plus the number of nonra-dioact ive positive ions is equal to the total number of negative ions.

By the principle of electroneutrality, the concentration of all counter ions is equal to those of hxed ions, namely the exchange capacity (Q) throughout the membrane including its two surfaces, as represented by Equation 34.17 ... 

As already mentioned, the principle of electroneutrality must be fulfilled in charged polymers. Consequently, in freshly prepared p-doped polymers, anions must compensate the positive charges within the polymeric chains. However, spectroelectrochemical studies [114], electrochemical quartz microbalance (EQMC) measurements [115], and SIMS and XPS measurements [116] on the mechanism of ion transport during charging and discharging of conducting polymers prove that discharging involves not only the expulsion of... 

The principle of electroneutrality in aqueous chemical systems states that the sum of the concentrations of all positively charged ions (expressed in equivalents) equals the sum of the concentrations of all negatively charged ions, so that the overall charge of the solution is zero. (If this were not true, we would be constantly bombarded with electrical shocks ) When an equation based on the principle of electroneutrality is combined with equations provided by conservation of mass, and by the mass action law, Eq. [1-12], the equilibrium chemical composition of a system can be calculated. 

The diffusion flux and the electric transference flux are provided in Eqs. (21) and (22). The convective flux is zero. The principle of electroneutrality mandates that the concentration of all counterions is equal to those of fixed ions, viz., the exchange capacity of the membrane (Q) ... 

Q.l5.6 What is the principle of electroneutrality and how does it relate to ions dissolved in solution ... 

The quality of field and laboratory measurements varies. A common criterion for determining the quality of water analyses is the charge balance among the reported cation and anion concentrations (Freeze and Cherry, 1979). The principle of electroneutrality... 

Prove the following relations using the principles of electroneutrality and mass balance ... 

The principle of electroneutrality requires that the ionic species in an electrolyte solution remain charge balanced on a macroscopic scale. The requirement of electroneutrality arises from the large amount of energy required to separate oppositely charged particles by any significant distance against Coulombic forces (e.g., Denbigh, 1971). Because of this requirement, we cannot obtain a flask of sodium ions at the chemistry supply room, nor can we measure the activity coefficients of individual ions directly. 

Overbeek s stricture noted above focuses attention on the principal reason why the current methods of imparting colloid stability are so few in number. The paramount difficulty resides in the projection of the repulsion over distances comparable to that of the attraction (5-10 nm). One way to accomplish this is to use Coulombic repulsion. In the electrostatic stabilization of aerosols, the Coulombic repulsion between the colloidal particles is of a long ran character and can impart stabUity. In liquid dispersion media, however, the principle of electroneutrality demands that the net charge in the dispersion medium be equal, but opposite in sign, to that of the particles. This leads to a more rapid fall-off in the potential. The coimterions in the dispersion medium, however, give rise to the electrical double layers that surround the colloidal particles. It is the mutual repulsion of these double layers that provides stability in electrostatic stabilization (see Fig. 1.2). 

Both models are one-dimensional and based on the principles of electroneutrality and conservation of mass and charge. Isothermal conditions are assumed and relationships between the... 

A literal interpretation of the equilibrium in [13] would be that, in order to keep electroneutrality in the resin phase, the sorption of a dicharged ion must be accompanied by desorption of two monocharged ions. At a first glance, eqn [17], therefore, seems to violate the principle of electroneutrality in the resin phase. However, the concentration for all types of ions in the external electrolyte is in equilibrium with the resin phase. In this particular case, this implies that the sorption of a dicharged ion will to a certain extent be accompanied by a sorption of the co-ion to the resin phase so that electroneutrality in the resin phase is maintained. 

Membranes may have various physical and chemical structures and hence are able to restrict transport processes by having different permeabilities for different substrates. Determining properties of equilibrium across and within a membrane may help in understanding the transport phenomena through membranes. Besides thermal equilibrium, the principle of electroneutrality is also satisfied. Because of the absence of mechanical equilibrium, a pressure difference known as osmotic pressure exists between subsystems separated by the membrane. In the case of substrates in ion form, both nonpermeating and permeating ions create an electrical potential difference known as membrane potential across the membrane. For the separated parts of A and B, electrochemical equilibrium for permeating species k is... 

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