Volta problem

Eq. (36) and (37) obtained by Frum-kin [1-5] can be classified as the solution of the famous Volta problem of the nature of emf of electrochemical circuit. Equation (37) demonstrates that the difference of potentials of zero charge (pzc) of two metals is approximately equal to their Volta potential. In as much as the Volta potential is equal to the difference of... 

Volta problem of the nature of the emf of an electrochemical circuit. The Volta potential difference for the liquid metal solution interface can be determined by using the following cell reference electrode solution inert gasjHgjsolutionjreference electrode, when the solution flows to the system through the internal walls of a vertical tube, where metal (e.g., mercury) flows out via a capillary placed axially in a vertical tube and is dispersed into drops. These metal drops carry away the free charges, thus, eliminating the potential difference in inert gas between the metal and the solution. A similar technique can be used for the solution j solution interface. There are also other techniques to determine the Volta potential difference [ii-vj. 

A computer program developed hy Volta handles the problem of condensing in the presence of a noncondensable gas for down-flow of either a saturated or superheated gas-vapor mixture vertical tubes. The program is based on a modification of Colburn-Hougen and Bras and is certainly more accurate and easier to use than the lengthy manual calculations. Although the program was written for vertical tubes, it can be used to approximate the results in a horizontal unit, and if the correction factor between vertical and horizontal tube condensation is applied, the compari-... 

A critical examination of the volta potential method has been made by Parsons (40) and by de Bethune (41) and some of the problems of this approach have been summarized by Halliwell and Nyburg (39). Randles (42) has obtained a value for AG° abs. hyd. for H+(g) by a procedure in this category and this combined with entropy estimates yields the value for Wn+ accepted by Rosseinsky (38) in his review, namely —269.7 kcal mole-1. 

In Chap. XX, Sec. 3, we spoke about the detachment of electrons from atoms, and in Sec. 4 of that chapter we took up the resulting chemical equilibrium, similar to chemical equilibrium in gases. But electrons can be detached not only from atoms but from matter in bulk, and particularly from metals. If the detachment is produced by heat, we have thermionic emission, a process very similar to the vaporization of a solid to form a gas. The equilibrium concerned is very similar to the equilibrium in problems of vapor pressure, and the equilibrium relations can be used, along with a direct calculation of the rate of condensation, to find the rate of thermionic emission. In connection with the equilibrium of a metal and its electron gas, we can find relations between the electrical potentials near two metals in an electron gas and derive information about the so-called Volta difference of potential, or contact potential difference, between the metals. We begin by a kinetic discussion of the collisions of electrons with metallic surfaces. 

Note that in chapter 1.5 and elsewhere in the present volume, we generally use yi as the symbol for potential. This is current usage and no problems arise as long as no phase boundaries have to be crossed. Here we prefer 0 to stress that we are dealing with an inner, or Gatvani potential, and not with a Volta potential (symbol yf)-... 

Surface tension and Volta potential measurements of aqueous electroljde surfaces can be supplemented by electrophoresis studies. Although the technical problems are the same as for the water surface in its pristine state, the interpretation is slightly easier because of the swamping nature of the electrolyte. We... 

The thermodynamic analyses used in this chapter make use of the electrochemical potential. In this way the electrical aspects of the interfacial equilibria are clearly defined. Earlier work on this problem, especially that by Volta and Nernst, had led to different conclusions regarding the source of the EMF in an electrochemical cell [12]. This problem was resolved by Frumkin, essentially, by writing out the interfacial equilibria using electrochemical potentials. In this regard, all interfaces in the cell must be considered including those between different metals at the terminals of the cell. This was shown in the discussion of the thermodynamic basis of the Nernst equation. 

Humphry Davy was not only an exceptionally gifted scientist, he also had remarkable social talents, and it is typical of him that already as a young man his career was sponsored by such luminaries in British science as Sir Joseph Banks, Henry Cavendish and Benjamin Thompson (Count von Rumford). He was also a great communicator, who from an early age made a name for himself in the popularization of science. At the same time, he had an intuition in scientific matters that allowed him to select problems that would prove to be fruitful and important. His work on electrolysis using Alessandro Volta s newly invented pile is a good example of this. He was convinced that in electrolysis the current induced the separation of compounds into their elementary components rather than the synthesis of new substances, as many scientists believed at the time. 

T. von Karman, The Problem of Resistance in Compressible Fluids, Atti del Convegno della Fondazione Alessandro Volta 1935, 223-326,1936. 

Instrumentation. Reported examples are mostly related to corrosion studies the particular problems in relating Volta potential differences as measured with an SKP and local corrosion potentials have been treated in detail [209]. The effect of barrier layers and metal surface pretreatment has been investigated [214,215]. In a study of the effect of a corrosion protection primer that contains the intrinsically conductive... 

One of the major problems encountered with the Volta pile was severe corrosion of the metals, and many early experiments were directed towards solving this problem. Thus it is apparent that batteries and corrosion are closely linked and, indeed, both are oxidation and reduction reactions. Oxidation and reduction is also involved in the related process of electrolysis, which underlies electroplating, a method of preventing corrosion. Finally, oxidation and reduction reactions underpin all life processes, although this aspect is not covered here. 

Recent progress and main problems of the study of electrochemical equilibrium properties are reviewed for interfaces between two immiscible liquid electrolyte solutions. The discussed properties are mainly described in terms of the Galvani, Volta, zero charge, and surface (dipolar) potentials at the liquid-liquid interfaces and free liquid surfaces. Different galvanic and voltaic cells with liquid-liquid, mainly water-nitrobenzene interfaces, are described. These interfaces may be polarizable or reversible with respect to one or several ions simultaneously. 

The aim of this chapter is to provide a short review covering the present state of research and knowledge, as well as the problems concerning electrochemistry of liquid interfaces at equihbrium. These systems are best described by mutually related chemical parameters, such as ion transfer energy, A%Gi, and electrical parameters, such as Galvani and Volta potentials, A cp and A%,xp, where s and w refer to the system consisting of organic and aqueous phases mutually saturated. It is well known that both these potentials can be correlated with the difference of surface potentials of the s... 

Conditions (1) and (4) are typical for all investigations of the Volta potentials. There are no serious problems with reahzing condition (2). It is also important to satisfy this condition in the studies of the differences of distribution potentials with the use of Eq. (35), i.e. by the method of voltaic cells [68-78]. In the above investigations, type-XVII cells are employed. As it can be easily proved, substitution of the electrolyte M X by M2X2, when the conditions (1), (2), and (4) are satisfied, leads to a change of the compensation voltage, AE17, defined by the equation ... 

Maystrenko, V. N., Evtyugin, G. A., Sidehukov, A. V. (2011). Volta metric Electronic Tongue Problems of Analytical Chemistry. Science, 14,285-313. 

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