Svante August Arrhenius , 1859-1927, Swedish chemist. He was a professor of physics in Stockholm in 1895 and became director of the Nobel Institute for Physical Chemistry, Stockholm, in 1905. For originating (1884, 1887) the theory of electrolytic dissociation, or ionization, he received the 1903 Nobel Prize in Chemistry. He also investigated osmosis and toxins and antitoxins. His works, translated into many languages, include Immunochemistry (1907), Quantitative Laws in Biological Chemistry (1915), The Destinies of the Stars (tr. 1918), and Chemistry in Modern Life (tr. 1925).

Arrhenius, Svante

COFOUNDER OF MODERN PHYSICAL CHEMISTRY
1859–1927

Svante August Arrhenius, born in Vik, Sweden, is regarded as the cofounder of modern physical chemistry. For his theory of electrolytic dissociation, Arrhenius received the Nobel Prize in chemistry in 1903. He also made important contributions to chemical kinetics and many other branches of science.

In 1884 Arrhenius obtained his Ph.D. from the University of Uppsala with a thesis on the conductivities of electrolytic solutions. Although poorly rated by his examiners, his thesis attracted the attention of the most distinguished physicists and physical chemists in Europe at the time. Arrhenius collaborated with a number of them from 1886 until 1890. Based on his international reputation, he secured a post at the Technical High School in Stockholm, first as a lecturer, then as a professor, and finally as its rector. He later became director of the new physical chemistry institute of the Nobel Foundation in 1905. By that time, his interests had already shifted toward other fields of science.

Arrhenius is mainly known for his equation describing the temperature dependence of chemical reaction rates:

k = A exp(−E /RT )

with k being the reaction rate constant, A a preexponential factor, E the activation energy, R the gas constant, and T the absolute temperature. Although the equation was first formulated by Dutch physical chemist Jacobus Hendricus van't Hoff in 1884, Arrhenius provided the interpretation of it that is still in use today. He suggested that the crucial step in a chemical reaction was the formation of activated molecules from the reactant molecules and that both states were in equilibrium , separated from each other by the activation energy E. Accordingly, he explained the temperature dependence of the reaction rate as a change of equilibrium, such that with increasing temperature more activated molecules were formed to undergo reaction. Furthermore, plotting the experimental results of ln k against 1/T (the so-called Arrhenius plot) yielded in many cases a straight line, from the slope of which one could easily calculate the activation energy E.

Arrhenius's most famous contribution, making him with the German physical chemist Friedrich Wilhelm Ostwald and van't Hoff a cofounder of modern physical chemistry, was his theory of electrolytic dissociation. Electrolytes are substances such as salts, acids, and bases that conduct electric current in solutions. Arrhenius suggested that every electrolyte, once dissolved in a solvent like water, dissociated into oppositely charged ions to a certain degree that depended on its nature and overall concentration. Before this explanation, chemists had continued to believe that electrolytes dissolved as uncharged molecules that could be separated only by strong electric forces, such as in electrolysis. Although the forces for electrolytic dissociation remained unclear for some time, Arrhenius's assumption could explain a wide range of phenomena and laws beyond electrochemistry. This included Raoult's laws of vapor pressure lowering and freezing point depression, Ostwald's dilution law, and van't Hoff's law of osmotic pressure of solutions. As Ostwald later showed in his acid-base theory, it also provided a quantitative understanding of the chemical activities of electrolytes in solution.

In his later years, Arrhenius applied the concepts of physical chemistry and physics to many other branches of science, including biochemistry, geoand cosmic physics, and meteorology. In retrospect, his most remarkable contribution was perhaps his model of the greenhouse effect , according to which the temperature of Earth's lower atmosphere is determined by the concentration of carbon dioxide. Earth's surface, after being warmed by sunlight, emits energy in the form of infrared radiation, which is absorbed by molecules in the atmosphere, particularly carbon dioxide; the absorption of infrared radiation leads to heat. At that time, the greenhouse effect model was used to explain the glacial periods, rather than any climatic changes induced by the human production of carbon dioxide, as is the case today.

see also Global Warming; Ostwald, Friedrich Wilhelm; van't Hoff, Jacobus.

Joachim Schummer

Bibliography

Crawford, Elisabeth (1996). Arrhenius. From Ionic Theory to the Greenhouse Effect. Canton, MA: Science History Publications.

Snelders, H. A. M. (1970). "Arrhenius, Svante August." In Dictionary of Scientific Biography, Vol. I, ed. Charles C. Gillispie. New York: Scribner.

Svante August Arrhenius

The Swedish chemist and physicist Svante August Arrhenius (1859-1927) is known for his theory of electrolytic dissociation.

Svante Arrhenius was born on Feb. 19, 1859, at Vik near Uppsala, the son of Svante Gustav and Carolina Thunberg Arrhenius. His father was a land surveyor and later a supervisor at the University of Uppsala.

Arrhenius's intellectual abilities became obvious early. Against his parents' wishes, the blond, blue-eyed, rubicund child taught himself to read at the age of 3. He acquired a fantastic arithmetical skill and a pictorial memory by observing his father adding columns in his account books. In his future scientific work, he was especially fond of discovering relationships and laws from masses of data. At the age of 8, he entered the fifth grade of the cathedral school, where he distinguished himself particularly in physics and mathematics and from which he graduated, the youngest and ablest student, in 1876.

Theory of Electrolytes

Arrhenius entered the University of Uppsala, where he studied chemistry, physics, and mathematics. As he was not satisfied with his chief instructor in physics, he left Uppsala in 1881 to work on the conductivities of electrolytes at Stockholm under the physicist E. Edlund. In 1884 Arrhenius presented his results (Recherches sur la conductibilité galvanique des électrolytes ) together with a new theory of electrolytes (Théorie chimique des électrolytes ) in a 150-page dissertation for the doctorate at Uppsala. Although he compromised and moderated his radical ideas, his professors were not impressed and only grudgingly passed the dissertation.

Arrhenius's theory of electrolytes encountered widespread resistance from the scientific world, but it eventually found confirmation in the modern theory of atomic structure. Of the 56 theses advanced in his 1884 dissertation, only a few have not withstood the test of time or have had to be greatly modified. In order to explain the nonconductance of solid salt and pure water when tested separately and the conductance of an aqueous salt solution, Arrhenius postulated that when a solid salt is dissolved in water its molecules dissociate or ionize into charged particles, which Michael Faraday had called ions years before. Whereas Faraday assumed that such ions are produced only during electrolysis, Arrhenius proposed that they are already present in solution even without the application of an electric current. Chemical reactions in solutions are thus reactions between ions. Arrhenius's views were essentially correct for weak electrolytes (weak acids, bases, and other covalent substances), but for strong electrolytes his ideas were modified in 1923 by the Debye-Hückel theory of inter-ionic attraction.

Professional Recognition

With the aid of a travel grant from the Swedish Academy of Sciences, Arrhenius devoted his next few years to travel and study. He worked with Wilhelm Ostwald in Riga and Leipzig, with Friedrich Kohlrausch in Würzburg, with Ludwig Boltzmann in Graz, and with J. H. van't Hoff in Amsterdam.

In 1891 Arrhenius was appointed lecturer and in 1895, over strong objections, professor of physics at the Technical University of Stockholm, of which he became rector in 1896. During this time he courted and married Sofia Rudback. The couple had a son, Olav Vilhelm, who became a worker in soil science and agricultural botany. Three children were born of his second marriage, to Maria Johansson.

In 1901 Arrhenius was elected, with strong opposition, to th Swedish Academy of Sciences. The following year he received the Davy Medal of the Royal Society, and in 1903 he became the first Swede to receive the Nobel Prize in chemistry for his theory of electrolytic dissociation. He was appointed rector of the newly founded Nobel Institute for Physical Research at Stockholm in 1905, a position he held until his retirement in the spring of 1927.

Spectrum of Scientific Achievement

After his theory was accepted by the entire scientific world, Arrhenius turned his attention to other topics. He became interested in the widest application of the fundamental theory of chemical reactions. In 1902 he began to apply the laws of theoretical chemistry to physiological problems, especially those of serum therapy (immunochemistry). He found that organismic changes follow the same laws as ordinary chemical reactions and that no essential difference exists between reactions in the test tube and those in the human body.

Arrhenius became active in the fields of astronomy and cosmic physics, and he proposed a new theory of the birth of the solar system by the collision of stars. He used the ability of radiation pressure to transport cosmic material to explain comets, the corona, the aurora borealis, and zodiacal light. He also hypothesized that spores of living matter are transported by radiation pressure from planet to planet with the resultant spread of life throughout interstellar space. He developed a theory to explain the ice ages and other profound climatic changes undergone by the earth's surface. He reflected upon the world's supply of energy and the conservation of natural resources. He dreamed of a universal language and proposed a modified form of English. There was hardly a field of science to which he did not make original, if not universally accepted, contributions. During his last years he wrote several textbooks and many books of a popular nature, in which he made it a point to indicate what was still to be done in the fields under discussion. Arrhenius had a healthy constitution, but he made great demands upon himself in order to maintain his extraordinary productivity. After a brief attack of acute intestinal catarrh in September 1927, he died on October 2 and was buried in Uppsala.

Further Reading

The biography by Wilhelm Palmaer, "Svante Arrhenius, 1859-1927," originally in German, appears in an abridged translation in Eduard Farber, ed., Great Chemists (1961). A thumbnail sketch of Arrhenius and a brief evaluation of the electrolytic dissociation theory are contained in Eduard Farber, Nobel Prize Winners in Chemistry, 1901-1961 (1963). Benjamin Harrow, Eminent Chemists of Our Time (1920), explains how Arrhenius formulated his theory of electrolytic dissociation. A popularized summary of his life and work may be found in Bernard Jaffe, Crucibles: The Story of Chemistry, from Ancient Alchemy to Nuclear Fission (1930; rev. ed. 1948).

Additional Sources

Svante Arrenius, 1859-1927, Moskva: "Nauka," 1990.

Crawford, Elisabeth T., Arrhenius: from ionic theory to the greenhouse effect, Canton, Mass.: Science History Publications/ USA, 1996. □