Theory Of Electrolytic Dissociation Research Articles

Трудни теми в учебната програма по химия от гледна точка на учениците

Chemistry is often considered a difficult subject, and the way students perceive learning affects their achievements. The research aims to identify: the topics in the secondary Chemistry curriculum perceived as difficult and as interesting by the Bulgarian students, the reasons for students’ difficulties and ways to overcome it. An inquiry was conducted with 321 students aged 16 – 17 years. According to them, the most difficult topics are Organic Chemistry and Chemical calculations (abstract and requiring specific skills). The most interesting topics are Organic Chemistry and Theory of Electrolytic Dissociation. Acids and bases. There is no significant correlation between levels of perceived difficulty and interest. Students relate difficulties to: information overload, emphasis on memorization, and lack of connections to everyday life. More lab activities and the practical application of the knowledge are recommended. Our research results can help improve Chemistry curricula and teaching practice.

Self-Control of Students for Educational Activities in the Context of Updated Educational Content

The concept of updating the content of education guides the teacher’s work towards the formationof common moral values, human kindness, a system of self-control and independent activity ina student.Updating the content of secondary education is associated with the provision of a new quality ofeducation; with the strengthening of the personality orientation of education; with updating its content;with the establishment of an effective relationship between teacher assessment and student self-control;with the conversion of student and teacher reflexes into means of assessment.Students’ self-control over their educational activities when teaching subjects at school can allowthem to gradually set learning objectives and independently evaluate their decisions; develop volitionalactivity, understand the individual parts of their educational activities, combine them into a commonstructure and interact with other classmates in solving the problems of their educational activities. A newlevel of quality education will be achieved through the formation and implementation of self-control oftheir educational activities in the learning process of students.The methods and tools used in a chemistry lesson that allow students to control their learning activitiesare discussed in the article. The above example from the section “Theory of electrolytic dissociation” of a school chemistry course shows the possibility of using a technological map as one of the methodsfor organizing students’ self-control over their educational activities.Based on the data of the pedagogical experiment, in which 52 students from Almaty schools participated,it was proved that the methods of self-control in learning positively affect the quality of learningoutcomes in chemistry, which is associated with self-control of students over educational activities inchemistry in high school.Key words: quality of education, sustainable development, educational activities, self-control, technologicalmap, content of updated education, assessment.

Priority of V. A. Kistyakovskii in the Discovery of Hydration

The priority of V.A. Kistyakovskii in the discovery of hydration was substantiated. The history of D.I. Mendeleev’s chemical theory of hydrates and S. Arrhenius’ physical theory of electrolytic dissociation was considered; the Kistyakovskii concept spans these theories. The role of I.A. Kablukov in hydration research and modern aspects of the theory were discussed.

On the Theory of Electrolytic Dissociation, the Greenhouse Effect, and Activation Energy in (Electro)Catalysis: A Tribute to Svante Augustus Arrhenius.

Svante Augustus Arrhenius (1859, Vik - 1927, Stockholm) received the Nobel Prize for Chemistry in 1903 "in recognition of the extraordinary services he rendered to the advancement of chemistry by his electrolytic theory of dissociation". Arrhenius was a physicist, and he received his PhD from the University of Uppsala, where he later became a professor for phyiscal chemistry, the first in the country for this subject. He was offered several positions as professor abroad, but decided to remain in Sweden and to build a Nobel Institute for physical chemistry using the Nobel funds. He remained director of the Institute until his death. There are powerful lessons to take from Svante August Arrhenius' journey leading to a Nobel laureate as there are from his tremendous contributions to chemistry and science in general, including climate science, immunochemistry and cosmology. The theory of electrolytic dissociation for which Arrhenius received the 1903 Nobel Prize in Chemistry has had a profound impact on our understanding of the chemistry of solutions, chemical reactivity, mechanisms underlying chemical transformations as well as physiological processes. As a tribute to Arrhenius, we present a brief historical perspective and present status of the theory of electrolytic dissociation, its relevance and role to the development of electrochemistry, as well as some perspectives on the possible role of the theory to future advancements in electroanalysis, electrocatalysis and electrochemical energy storage. The review briefly highlights Arrhenius' contribution to climate science owing to his studies on the potential effects of increased anthropogenic CO2 emissions on the global climate. These studies were far ahead of their time and revealed a daunting global dilemma, global warming, that we are faced with today. Efforts to abate or reverse CO2 accumulation constitute one of the most pressing scientific problems of our time, "man's urgent strive to save self from the adverse effects of his self-orchestrated change on the climate". Finally, we review the application of the Arrhenius equation that correlates reaction rate constants (k) and temperature (T); , in determining reaction barriers in catalysis with a particular focus on recent modifications of the equation to account for reactions exhibiting non-linear Arrhenius behavior with concave curvature due to prevalence of quantum mechanical tunneling, as well as infrequent convexity of Arrhenius plots due to decrease of the microcanonical rate coefficient with energy as observed for some enzyme catalyzed reactions.

Unified Thermodynamics for All Concentrations of Electrolytes Based on Hydration and Partial Dissociation (Without Activity Coefficients, 1995-)

Twenty years ago in the ECS meeting at Reno, May 1995, the author presented her breakthrough paper on the partial dissociation and hydration of NaCl from ‘zero to saturation’. This totally replaced the idea of complete dissociation and the activity coefficient corrections in thermodynamics and confirmed the theory of electrolytic dissociation founded over a century ago by Svante Arrhenius for which he was awarded the Nobel Prize in 1903. According to his original theory (1884 - ), a fraction (α ) mole of an electrolyte like NaCl dissociates in water into 2α moles of ions, the rest (1-α)being in the undissociated form: NaCl (1- α ) ↔ Na+( α ) + Cl- ( α ) (1) Thus every mole of salt increased to (1-α) + 2α = (1+α) = i ( >1) moles of solute on dissolving in water. With the ratio of the equivalent conductivity at any concentration (L) to that at infinite dilution (Lo) as a measure of the degree of dissociation (α),this factor, i, called van't Hoff factor, explained the increase in osmotic pressure as observed by van't Hoff. This theory was greatly successful in explaining many other properties of dilute electrolyte solutions. While attempts were in progress to extend the theory to concentrated solutions, the thermodynamics of solutions was replaced (Lewis and Randall, 1921) by that of the empirical concepts of activity and activity coefficients. Since the Debye-Huckel theory of interionic interaction for completely dissociated electrolytes, as shown: NaCl → Na+ + Cl- (2) was able to nearly explain the concentration dependence of activity coefficients for very dilute solutions, the latter equations based on complete dissociation were gradually extended to higher concentrations until they resulted in extremely elaborate equations (Pitzer, 1973) without physical significance. The author became aware of the complexity of the theory of simple electrolytes like NaCl (aq) during her doctoral work on strong electrolytes. In the following years, she abandoned this theory and started reinvestigating the available experimental data on the properties of electrolytes (Heyrovska, 1979, 1980). Gradually it became clear that, with the degrees of dissociation (α)and the hydration numbers evaluated by the author from the vapor pressure (or osmotic coefficient) data (instead of from the conductivity ratio), the original idea of partial dissociation due to Arrhenius, as per equation (1), and of 'free water' (Bousfield, 1917), could explain quantitatively the non-ideal properties of electrolytes over a large range of concentrations (Heyrovska, 1987, 1988). Further advance was made by the author in 1995 on realizing that the molalities of ‘free’ water in the "surface and bulk of solution" are different. This made a breakthrough in the theory of electrolytes, which could then be extended to the whole range of concentrations from "zero to saturation" (Heyrovska, 1995, 1996) for the first time. Many thermodynamic properties of solutions could thus be explained quantitatively in terms of simple mathematical relations involving the degrees of dissociation, hydration numbers and volumes of ions and ion pairs, without any empirical parameters. For review papers on the subject, see Heyrovska, 1998, 2003, 2006, 2011 and 2013. For a complete list of references and Table of equations, see Refs. 11,12 below and the literature therein. Full list of all publications are in: www.jh-inst.cas.cz/~rheyrovs. Some selected references pertaining to the ‘whole concentration range’ are given below.

ELECTRICAL CONDUCTIVITY OF AQUEOUS SOLUTIONS AND ELECTROLYTIC DISSOCIATION

A new theory of electrolytic dissociation and proton-electron conductivity of aqueous solutions was proposed. It supposed to be alternative to the theory of electrolytic dissociation S. Arrhenius and ionic conductivity. In liquid state molecules of water are associated into the clusters, forming fractal cluster-clathrate structures. Number of water molecules in the cluster is not precisely determined. Obviously, their number in the cluster is variable, which depends on the temperature of the aqueous system and other factors that determine the state of the aqueous system.Electrical conductivity and ionization of the water system components are determined by the proton-electron interaction of water clusters with each other and with dissolved and/or suspended solids in the water system. Also this parameters are strongly affected by various physical-mechanical, physical and physicochemical effects, such as change of the hydrodynamic regime of moving water, mechanical and physical factors: pressure, temperature change, sound, magnetic and electric fields, UV radiation, dissolved and suspended substances (silicates, aluminum silicates, dissolved oxygen, carbon oxide (IV), bicarbonates, calcium, magnesium, iron, etc).The dissociation of the electrolytes in the aqueous solution not occurs spontaneously. It is carried out under the influence of chemical reactions. Therefore, in an aqueous solution free ions (cations and anions) do not exist.

ChemInform Abstract: Solution Phase Thermodynamics of Strong Electrolytes Based on Ionic Concentrations, Hydration Numbers and Volumes of Dissolved Entities

AbstractReview: 54 refs.

Solution phase thermodynamics of strong electrolytes based on ionic concentrations, hydration numbers and volumes of dissolved entities

This article summarizes the successful restoration of Arrhenius’ theory of electrolytic dissociation founded 130 years ago. His idea of using the conductivity ratio for the degree of dissociation was a breakthrough in interpreting the properties of dilute solutions. For higher concentrations, as it was not satisfactory, attempts were being made to improve the methods of obtaining the degrees of dissociation. However, the latter was prematurely replaced by the empirical activity coefficient correction factors. Subsequently, the success of the Debye–Huckel (D–H) theory of inter-ionic interaction between free ions in explaining the properties of dilute solutions was taken to mean complete dissociation at all concentrations and interpretation of solution properties amounted to extending the D–H equations by the gradual addition of more parameters. At the end of six decades the equations became so complex that they failed to provide a unified interpretation of the causes of non-ideality at all concentrations and a molecular insight into the observed phenomena. Therefore, the present author abandoned them and started investigating the available experimental data as such. Using the degrees of dissociation and surface and bulk hydration numbers evaluated from solution vapour pressures, the author was able to interpret solution properties based on the idea due to Arrhenius a century earlier. Presented here is a comparison of the complicated equations based on complete dissociation with the simple equations obtained based on partial dissociation, hydration and volumes of entities in the solution. All the main equations are summarized in the table.

В. Ю. Чаговець – перший мембранолог України: життєвий і творчий шлях

Vasyl Chagovets was first to apply the theory of electrolytic dissociation in electrophysiology, formulated the ionic theory of origin of bioelectric potentials and condenser theory of electric irritation of living tissues. He proposed using electrogastrogram as a research method of secretory function of stomach. He first by grounded expedience of application of mathematical methods in biology. Keywords: V. Yu. Chagovets, condenser theory of excitation, bioelectrogenesis.

De Svante Arrhenius ao peagâmetro digital: 100 anos de medida de acidez

This work describes the establishment of the concept of pH and the evolution of its measurement. The origin of the pH definition can be found in the development of the chemistry of aqueous solutions during the XIXth century. The electrolytic dissociation theory by Svante Arrhenius played a central role. After the proposal of the pH scale by Sorensen, many years were necessary for the acceptance of this new parameter among chemists in general. Its importance was first recognized in biochemistry and related areas. Twenty years after, its importance had been recognized in many industrial and laboratorial practices. The previous methods were based on colorimetric and electrometric methods, but both suffered from many problems. Acceptance of pH in Chemistry was only possible after the development of experimental trustable measurements. The invention of the pH meter was the primordial step.

The Development of the Theory of Electrolytic Dissociation

The theory of electrolytic dissociation proved to be one of the most controversial in the history of chemistry. This paper examines the evidence proffered by Arrhenius, van't Hoff, and Ostwald in favour of the theory and outlines the objections raised by Armstrong, Fitzgerald, and Pickering. The controversy revolved partly around the nature of the emerging new chemistry and has important implications for the study of the nature of science. Some important observations are made in relation to the teaching and learning of chemistry.

A Century of Chemical Dynamics Traced through the Nobel Prizes. 1903: Svante Arrhenius

This, the second of a series of thirteen articles on Nobel Laureates in chemical dynamics, features the work of Svante Arrhenius, who won the Nobel Prize in 1902 for his electrolytic theory of dissociation. The first article in this series, which appeared in the December 2001 issue of this Journal discussed Jacobus van't Hoff's contribution to our understanding of the nature of molecules in solution and to the study of solution-phase reaction dynamics. Arrhenius's electrolytic dissociation theory extended van't Hoff's ideas about the nature of molecules in solution into the realm of aqueous salts and acids and bases. Not only did this allow for correction of the van't Hoff equation as applied to electrolytes (the so-called van't Hoff i-factor), but it also showed how van't Hoff's principles of chemical dynamics could be applied to ionic solutions. The studies of catalysis by Ostwald (Nobel 1909, to be discussed in the February 2002 issue of this Journal in the next essay in this series) were guided by the work of van't Hoff and Arrhenius, both of whom had worked with Ostwald. Although it was not mentioned specifically in his Nobel presentation, the well-known Arrhenius equation relating reaction rate constants to activation energies and temperature is fundamental to all subsequent studies of reaction energetics and catalysis, and no modern discussion of chemical dynamics could begin without it. Arrhenius is best remembered today by teachers and students of chemistry because the definition of acids and bases and also the equation relating reaction rate constants to temperature through the activation energy that are both named for him.

UN'INFANZIA DIFFICILE: LA TEORIA DELLA DISSOCIAZIONE ELETTROLITICA NEL XIX SECOLO

Abstract<title> SUMMARY </title>The theory of electrolytic dissociation represented the main chapter of modern chemistry-physics born in the last decades of 19th century. It was vigorously supported, in particular by Ostwald, Arrhenius and Nerst, but it was also harshly criticised. This paper reconstructs the theorical and empirical arguments, which were proposed for and against this theory. Namely, it shows on the one hand the great difficulties, that the supporters of the theory were faced with, and on the other hand the strategies that they adopted in order to overcome these problems. The final part discusses how certain models for a philosophical reconstruction of science shed light on this historical case.

Chemical kinetics and the origins of physical chemistry

Physical chemistry is commonly said to have become established as a recognized field of science in the eighteen-eighties. The year 1887 was indeed of special significance, for it was then that the Zeitschriftfiir physikalische Chemie was founded by OSTWALD and VAN'T HOFF, that ARRnENIUS published his famous theory of electrolytic dissociation, 1 that OSTWALD was appointed professor of physical chemistry at the University of Leipzig, and that the second and final volume of OSTWALD'S Lehrbuch der allgemeinen Chemie 2 was published. I t is true that OSTWALD was the second occupant of the chair of physical chemistry at Leipzig, the first having been the physicist F. W~EDEMANN who had assumed the position in 1871. It is also the case that the expression 'physical chemistry' had been used as early as the eighteenth century 3. Work in the field prior to 1880 was, however, spasmodic; it was only during that decade that the subject gained momentum and became noticed by workers in other branches of science. There have been several accounts of the early years of physical chemistry, notably those of ROOT-BERNSTEIN 4 and of HIEBERT 5. These have emphasized in

Acid-Base Catalysis

THE establishment of a new truth invariably evokes a number of new fallacies; the brighter the light that a new theory sheds on its proper field, the darker, and the more distorting, the shadows in which it submerges the experience which lies around the borders of its true scope. The striking success of the theory of electrolytic dissociation based on mass action law blinded scientific workers for more than twenty years to the necessity of invoking a new principle for the explanation of the marked deviations from this law in solutions of neutral salts and strong acids and bases.

Obituary

PROF. HOLLAND CROMPTON, formerly professor of organic chemistry at Bedford College, London, who died on Dec. 22, 1931, was born in Preston, Lancashire, on April 30,1866. He attended school in Stuttgart and later studied chemistry under Prof. H. E. Armstrong at the City and Guilds Institute. In 1888 he was appointed lecturer and head of the Department of Chemistry at Bedford College, London, in succession to Spencer U. Pickering. He held this post until 1919, when the department was divided, and from that date until his retirement in 1927, on account of ill-health, he was head of the Department of Organic Chemistry. Crompton never enjoyed robust health, and in his later years it became steadily worse. He will be remembered by both organic and physical chemists on account of his work on acenaphthene, atomic energy and the specific heat of gases, molecular association and molecular magnitudes, osmotic pressure and the electrolytic dissociation theory.

The Dissociation Theory of Solution

IT is now forty-three years since the electrolytic dissociation theory was proposed by Arrhenius in 1887, to account for the changes in the physical properties of solutions caused by electrolytes, which had compelled Van't Hoff to introduce the coefficient i into the gas equation PV=RT.

Prof. Svante Arrhenius, for. Mem. R.S

THE annals science bear abundant testimony to the native genius and energy of Sweden, and in this respect Svante August Arrhenius, who has just passed away, upheld with honour and distinction the reputation of his country. Born near Upsala in 1859, as the son of a land steward, Arrhenius obtained his early education in the school and university of that town, moving later to the University of Stockholm, the atmosphere of which was more congenial and stimulating to the young physicist. His researches there on electrical conductivity and its relation to chemical activity, although lightly esteemed by the Upsala professors, brought him recognition abroad, whilst the theory of electrolytic dissociation, put forward in 1887 during his Wanderjahre, secured for him an established position in international science.

The Coefficient of lonisation of a Fused Salt

IT is now forty years since Arrhenius and Van't Hoff put forward two independent methods for calculating the ‘coefficient of ionisation’ of a dissolved salt. The general concordance of their results provided a firm foundation for Arrhenius's theory of electrolytic dissociation, whilst the smaller discordances have provided material for the development of the later theory of complete ionisation. Since neither of the above methods could be used to determine the coefficient of ionisation of a fused salt, it has been supposed that the problem of determining this coefficient was insoluble. All the data that are required for a formal solution are, however, available for silver chloride at 600°, namely, molecular weight M = 143.34,density = 5.267–0.00092 t = 4.715, specific conductivity k = 4.48, viscosity = 0.01606 (at 603°).

The Structure of the Atom1

THE GENERAL PICTURE OF THE ATOM. THE present state of atomic theory is characterised by the fact that we not only believe the existence of atoms to be proved beyond a doubt, butalso we even believe that we have an intimate knowledge of the constituents of the individual atoms. I cannot on this occasion give a survey ofthe scientific developments that have led to this result; I will only recall the discovery of the electron towards the close of the last century, which furnished the direct verification and led to a conclusive formulation of the conception of the atomic nature of electricity which had evolved since the discovery by Faraday of the fundamental laws of electrolysis and Berzelius's electrochemical theory, and had its greatest triumph in the electrolytic dissociation theory of Arrhenius. This discovery of the electron and elucidation of its properties was the result of the work of a large number of investigators, among whom Lenard and J. J. Thomson may be particularly mentioned. The latter especially has made very important contributions to our subject by his ingenious attempts to develop ideas about atomic constitution on the basis of the electron theory. The present state of our knowledge of the elements of atomic structure was reached, however, by the discovery of the atomic nucleus, which we owe to Rutherford, whose work on the radioactive substances discovered towards the close of the last century has much enriched physical and chemical science.