Data tables standard electrode

Both half-equations are written below as they appear in tables of data showing standard electrode potentials ... 

Thermodynamic data (4) for selected manganese compounds is given ia Table 3 standard electrode potentials are given ia Table 4. A pH—potential diagram for aqueous manganese compounds at 25°C is shown ia Figure 1 (9). 

The values in Table 2.16 show how the potentials obtained under service conditions differ from the standard electrode potentials which are frequently calculated from thermodynamic data. Thus aluminium, which is normally coated with an oxide film, has a more noble value than the equilibrium potential 3 + / = — 1-66V vs. S.H.E. and similar considerations apply to passive stainless steel (see Chapter 21). 

SOURCES The most authoritative source is S. G. Bratsch, J. Phys. Chem. Ref. Data 1989,18, 1. Additional data come from L. G. Sillen and A. E. Martell, Stability Constants of Metal-Ion Complexes (London The Chemical Society, Special Publications Nos. 17 and 25. 1964 and 1971) G. Milazzo and S. Caroti, Tables of Standard Electrode Potentials (New York Wiley, 1978) T. Muss ini,... 

It should be emphasized that many of the potentials listed in tables of standard electrode potentials are values calculated from thermodynamic data rather than obtained directly from cell emf data. As such they are valuable for calculating equilibrium constants of reactions, but caution should be exercised in using them to predict the behavior of electrodes. A steady value for an electrode potential does not necessarily represent the thermodynamic or equilibrium value. 

Standard electrode potential data are available for an enormous number of halfreactions. Many have been determined directly from electrochemical measurements. Others have been computed from equilibrium studies of oxidation/reduction systems and from thermochemical data associated with such reactions. Table 18-1 contains standard electrode potential data for several half-reactions that we will be considering in the pages that follow. A more extensive listing is found in Appendix 5. ... 

The data in this table are mainly taken from A. J. Bard, J. Jordan, and R. Parsons, Eds., Standard Potentials in Aqueous Solutions, Marcel Dekker, New York, 1985 (prepared under the auspices of the Electrochemistry and Electroanalytical Chemistry Commissions of lUPAC). Other sources of standard potentials and thermodynamic data include (1) A. J, Bard and H. Lund, Eds., The Encyclopedia of the Electrochemistry of the Elements, Marcel Dekker, New York, 1973-1986. (2) G. Milazzo and S. Caroli, Tables of Standard Electrode Potentials, Wiley-Interscience, New York, 1977. The data here are referred to the NHE based on a 1-atm standard state for H2. See the footnote in Section 2.1.5 concerning the recent change in standard state. 

Data for the potential of the silver electrode in the presence of selected ions are given in the tables of standard electrode potentials in Appendix, 5 and in Table 22-1. Similar information is also provided for other electrode systems. These data often simplify the calculation of half-cell potentials. 

Note that the appearance of a half-reaction in a table of electrode potentials does not necessarily imply that there is a real electrode whose potential corresponds to the half-reaction. Many of the data in such tables were calculated from equilibrium or thermal data, and thus, no actual potential measurements on the electrode system of interest were ever made. For some half-reactions, no suitable electrode is known. For example, the standard electrode potential for the process... 

Sources Data from Ionization energies cited in this chapter are from C. E. Moore, Ionization Potentials and Ionization Limits Derived fwm the Analyses of Optical Spectra, National Standard Reference Data Series, U.S. National Bureau of Standards, NSRDS-NBS 34, Washington, DC, 1970, unless noted otherwise. Electron affinity values listed in this chapter are from H. Hotop and W. C. Lineberger, J. Phys. Chem. Ref Data, 1985,14, 731. Standard electrode potentials listed in this chapter are from A. J. Bard, R. Parsons, and J. Jordan, eds., Standard Potentials in Aqueous Solutions, Marcel Dekker (for lUPAC), New York, 1985. Electronegativities cited in fiiis chapter are from J. B. Mann, T. L. Meek, and L. C. Allen, J. Am. Chem. Soc., 2000,122, 2780, Table 2. Other data are from N. N. Greenwood and A. Earnshaw, Chemistry ofthe Elements, Pergamon Press, Elmsford, NY, 1984, except where noted. J. Emsley, The Elements, Oxford University Press, New York, 1989. S. G. Bratsch, J. Chem. Educ., 1988,65, 34. 

In order to define a potential reference suitable for electrochemistry, a reference redox couple must firstly be chosen the H /H2 couple in its thermodynamic standard state. This reference system is called Standard Hydrogen Electrode (SHE). It is well-defined even though it is theoretical, and it is the reference used in all contemporary data tables in thermodynamics and electrochemistry... 

This book contains extensive tables of standard electrode potentials covering the periodic chart. For each electrode reaction Is given the standard potential, the temperature and the pressure, the solvent, and a literature reference. Occasionally the temperature coefficient of the electrode potential Is given together with an estimate of uncertainty. Much of the tabulated data Is taken from secondary sources (such as Item [149]). 

By devising various galvanic cells and measuring their electromotive forces, tables of values of standard electrode potentials can be constructed. A table that lists the value of electrode potential for any half-cell in which all concentrations are IM and all gases are at 1-atm pressure is a Table of Standard Reduction Potential (Table 3.2). By convention, the tabulated values are standard reduction potentials relative to the potential of the standard hydrogen electrode, which is defined as exactly zero volts. The analysis of the data from Table 3.2 highlights some important aspects. 

Table 19.1 Standard electrode potentials for some common metals (all data taken from the IB Chemistry data booklet)... 

Table 4. The entropy change on absolute scale, EPHs and Peltier coefficients for some standard electrode reactions in aqueous solution at 298.15K From Ref. [1], but recalculating a part of data according to Ref. [42]...

In the Technical Report on mercury(II) and silver(I) oxide electrodes, prepared by Rondinini et al. in the frame of the Conunission on Electroanalytical Chemistry of lUPAC [182], the results obtained by Longhi et al. [176] were taken as the basic data. Table 5.6.1 shows the standard potentials of the Hg HgO electrode given in this report. Potentials of both electrodes Hg HgO H and Hg HgO OH at different temperatures were reported. 

Nothing can be concluded about the relative potential energy of an electron at the standard electrode potential. Use data from Table 18.1 to calculate AG° for the reaction. 

Table 13.2 Standard electrode potentials at 25 °C (data from [5-7])...

The potential difference in an electrochemical cell at 25°C and 1.013 bar (1 atm) can be calcnlated by simply subtracting the left-hand standard electrode potential from the right-hand one. For example, nsing Table 4.1 data, the standard value of the... 

The standard electrode potential can be calculated using either thermodynamic data or found in a table of standard electrode potentials, so-called electrochemical series. The tabulated standard electrode potentials are available only at a temperature of 25°C and a pressure of 1.013 bar (not 1 bar). 

The electrical double layer at pc-Zn/fyO interfaces has been studied in many works,154 190 613-629 but the situation is somewhat ambiguous and complex. The polycrystalline Zn electrode was found to be ideally polarizable for sufficiently wide negative polarizations.622"627 With pc-Zn/H20, the value of Eg was found at -1.15 V (SCE)615 628 (Table 14). The values of nun are in reasonable agreement with the data of Caswell et al.623,624 Practically the same value of Eff was obtained by the scrape method in NaC104 + HjO solution (pH = 7.0).190 Later it was shown154,259,625,628 that the determination of Eo=0 by direct observation of Emin on C,E curves in dilute surface-inactive electrolyte solutions is not possible in the case of Zn because Zn belongs to the group of metals for which E -o is close to the reversible standard potential in aqueous solution. 

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