Giulio Milazzo

True temperature coefficients of the electric tension of individual electrodes—XI. Theoretical analysis of the procedure to obtain individual activity coefficients

Abstract Milazzos procedure for obtaining individual activity coefficients requires some non-thermodynamic considerations and some mathematical approximations. Each one of them is analyzed theoretically in order to reach an estimation of the reliability of the whole procedure. It is shown that the uncertainties arising from the approximations and from the non-thermodynamic considerations do not impair the basic principle of the procedure, and that the results will become more and more reliable as the experimental techniques are improved.

Sullo spettro ultravioletto di assorbimento del pirrolo e del N-deuteriopirrolo in fase gassosa

Zusammenfassung Es werden die Spektren des Pyrrols und des N-Deuteriopyrrols beschrieben. die aus einer beschrankten Anzahl sehr breiter und diffuser Banden mit einem uberlagerten Kontinuum bestehen. Der reine Elektronensprung weist fur beide Verbindungen denselben Betrag auf von ungefahr 47 300 cm −1 . Als Vorbanden kann man nur die Kernschwingungen 650 und 912 cm −1 beobachten (die letzte nur beim Deuteriopyrrol und auserdem zweifelhaft). Im angeregten Zustand findet man eine Frequenz von 1469 cm −1 fur das Pyrrol bzw. von 1054 cm −1 fur das Deuteriopyrrol. Das Verhaltnis dieser Frequenzen ist 1,40 wahrend das theoretische Verhaltnis zwischen der N-H- und der N-D-Valenzschwingung, unter der Annahme einer gleichen Elektronenkonfiguration beider Gruppen auch im angeregten Zustand, etwa 1,37 sein mus, so das diese Frequenzen mit sehr groser Wahrscheinlichkeit der N-H- bzw. der N-D-Valenz-schwingung zugeordnet werden konnen. Als Nachbanden kann man noch 2 Banden beobachten die derselben Schwingung fur beide Verbindungen im angeregten Zustand zuzuordnen sind. Die Frequenzen dieser Schwingung sind 1037 cm −1 fur das Pyrrol und 869 cm −1 fur das Deuteriopyrrol, mit einem Verhaltnis von 1,19. Sie entsprechen den Raman -Frequenzen 1204 und 1012 cm −1 des Pyrrols bzw. des Deuteriopyrrols, die dasselbe Verhaltnis 1,19 aufweisen. Diese Frequenzen mussen dann einer Schwingung zugeordnet werden, an der auch das H- bzw. D-Atom teilnimmt. das an daa N- Atom gebunden ist.

Spectrochemical Analysis in the Vacuum Ultraviolet with the Hollow-Cathode Light Source—Part I. Qualitative Analysis

The use of a cooled hollow-cathode light source of new design was investigated for quantitative spectrochemical analysis of iodine in the vacuum ultraviolet (VUV). The conditions of the discharge and all prerequisites were tested, taking into account many possible sources of error. The results, shown in Tables and in graphs, indicate that this kind of light source gives good results for spectrochemical analysis in the VUV, for elements having the most sensitive lines in this spectral region. The range covered in this investigation lies between 1 and 100 μg iodine in a 1-mg potassium chloride matrix.

True Temperature Coefficients of the Electric Tension of Individual Electrodes II. [Fe(CN)6]4− -[Fe(CN)6]3− Electrode

The [formula omitted] electrode was thoroughly investigated to ascertain whether, in addition to the influence of the activity coefficients, association phenomena should also be considered in studying the true temperature coefficients of the electric tension of individual electrodes. The influence of the associations (first step): [formula omitted] and the corresponding ones with Na+ ions on the true temperature coefficient of this electrode is shown.

Vacuum Ultraviolet Spectroscopy

A review is presented on vuv spectroscopy, discussing the optics necessary, instrumentation used in absorption and emission vuv, and measurement of wavelength and intensities. Finally, several applications of the technique of interest to the chemist are presented.

Reference electrodes and tensions

Abstract A critical review is made of problems — for which satisfactory solutions have not yet been reached — relating to reference and comparison electrodes and tensions. These problems include: absolute electrode tensions; tensions relative to the standard hydrogen electrode; accuracy of determination of tensions of hydrogen, silver/silver chloride and calomel electrodes; activity coefficients of single ionic species; diffusion tensions at liquid junctions between different solutions; isothermal and non-isothermal temperature coefficients of reference and comparison electrodes; problems of measurements in non-aqueous media. The paper describes processes and methods that are being used in order to improve our present knowledge of these problems, and to bring their solution nearer. In particular, for measurements at temperatures other than 25° and for those in non-aqueous media, the paper describes the attempts made to relate all measurements to a single reference electrode, i.e. to the single reference point on the tension scale as given by the standard hydrogen electrode, the tension of which is stated by definition to be equal to zero in water at 25°.

True Temperature Coefficients of the Electric Tension of Individual Electrodes III. Ag\AgCl\ Cl− Electrode

basis of an extended Debye-Hückel equation. The thus obtained values for dT as a function of the molality aro not constant and show a residual error arising probably from the non identity between mean and true ionic activity coefficients and perhaps from a small degree of association of LÌGI. The corrections arising from the ionic entropies of transport were shown to be unimportant for the particular electrolyte chosen (LiCl), probably remaining of the same order of magnitude as the experimental error, i.e. about 2°/0 and were therefore disregarded.

Versatile Hollow-Cathode Light Source for Spectrochemical Analysis in the Vacuum Ultraviolet

The development of the spectrochemical analysis of nonmetals progressed much slower than that of the metallic elements. This difference could probably be traced to the following reasons: (1) lack of sensitive spectroscopic lines in the visible or near ultraviolet region; (2) poor spectral sensitivity; (3) excitation difficulties; and (4) materials to be analyzed are often poor conductors and mechanically unworkable as electrodes. Some of these difficulties can be overcome by utilizing the vacuum ultraviolet spectral region (VUV), where the nonmetallic elements show their most sensitive spectral lines (i.e., resonance lines). The remaining difficulties can be ameliorated if an exciting source is provided, which allows these elements to be used as electrodes.

Abbreviated report of the ‘nomenclature and electrochemical definitions’ committee of C.I.T.C.E. and of the ‘symbols and electrochemical terminology’ sub-committee of I.U.P.A.C.

Abstract This is an abbreviated version of the report already published in this Journal (2 (1961) 265-290 and 6 (1963) 173) and was prepared by G. Millazo and P. van Rysselberghe. The translation into English was prepared by R. parasons and is presented here in order that a wider group of electro chemists and electro-analytical chemists may become aware of the direction in which Nomenclature discussions are taking. Comments direct to C.I.T.C.E. (Professor Pierre van Rysselberghe. Department of Chemistry, Stanford University, Stanford, California, U.S.A.) or (if in publishable form), to this Journal, will be welcome.

Ein Spektrograph für das Schumann-Gebiet

Zusammenfassung Es wird ein Vakuumspektrograph besonders fur das Schumanngebiet beschrieben, der aber auch in anderen Wellenlangegebieten verwendet werden kann. Dieser Spektrograph ist mit einem 1 m Konkavgitter ausgerustet mit 1200 Strichen/mm, mit einer geritzten Flache von 40 × 80 mm in Eagle-Montage, und zeichnet sich vor anderen ahnlichen Spektrographen dadurch aus, dass der Kassettenraum von dem Gitterraum licht- und vakuumdicht getrennt werden kann, sodass die Evakuierung nach jedem Platten Wechsel sehr schnell erfolgen kann. In diesem Spektrographen sind weiter einige andere konstruktive Verbesserungen verwirklicht, wodurch die Justierungsarbeit bedeutend vereinfacht wird.