referaty.sk – Všetko čo študent potrebuje
Viliam
Štvrtok, 28. mája 2020
The Nobel Prize in Chemistry
Dátum pridania: 21.08.2007 Oznámkuj: 12345
Autor referátu: holdenko
 
Jazyk: Angličtina Počet slov: 10 788
Referát vhodný pre: Gymnázium Počet A4: 37.9
Priemerná známka: 2.95 Rýchle čítanie: 63m 10s
Pomalé čítanie: 94m 45s
 

2. The First Decade of Nobel Prizes for Chemistry
So much fundamental work in chemistry had been carried out during the last two decades of the 19th century that, as stated by Westgren [1], "During the first few years the Academy was chiefly faced with merely deciding the order in which these scientists should be awarded the prize." For the first prize in 1901 the Academy had to consider 20 nominations, but no less than 11 of these named van't Hoff, who was also chosen by the Committee for Chemistry. van't Hoff had already during his thesis work in Utrecht in 1874 published his suggestion that the carbon atom has its four valences directed towards the corners of a regular tetrahedron, a concept which is the very foundation of modern organic chemistry. The Nobel Prize was, however, awarded for his later work on chemical kinetics and equilibria and on the osmotic pressure in solution, published in 1884 and 1886, when he held a professorship in Amsterdam. When he received the prize he had, however, left this for a position at Akademie der Wissenschaften in Berlin in 1896.

In his 1886 work van't Hoff showed that most dissolved chemical compounds give an osmotic pressure equal to the gas pressure they would have exerted in the absence of the solvent. An apparent exception was aqueous solutions of electrolytes (acids, bases and their salts), but in the following year Arrhenius showed that this anomaly could be explained, if it is assumed that electrolytes in water dissociate into ions. Arrhenius had already presented the rudiments of his dissociation theory in his doctoral thesis, which was defended in Uppsala in 1884 and was not entirely well received by the faculty. It was, however, strongly supported by Ostwald in Riga, who, in fact, travelled to Uppsala to initiate a collaboration with Arrhenius. In 1886-1990 Arrhenius did work with Ostwald, first in Riga and then in Leipzig, and also with van't Hoff in Berlin. When Arrhenius was awarded the Nobel Prize for Chemistry in 1903, he was since 1895 professor of physics in Stockholm, and he was also nominated for the Prize for Physics (see Section 1).

The award of the Nobel Prize for Chemistry in 1909 to Ostwald was chiefly in recognition of his work on catalysis and the rates of chemical reactions. Ostwald had in his investigations, following up observations in his thesis in 1878, shown that the rate of acid-catalyzed reactions is proportional to the square of the strength of the acid, as measured by titration with base. His work offered support not only to Arrhenius' theory of dissociation but also to van't Hoff's theory for osmotic pressure. Ostwald was founder and editor of Zeitschrift für Physikalische Chemie, the publication of which is generally regarded as the birth of this new branch of chemistry.

Three of the Nobel Prizes for Chemistry during the first decade were awarded for pioneering work in organic chemistry. In 1902 Emil Fischer, then in Berlin, was given the prize for "his work on sugar and purine syntheses". Fischer's work is an example of the growing interest from organic chemists in biologically important substances, thus laying the foundation for the development of biochemistry, and at the time of the award Fischer mainly devoted himself to the study of proteins. Another major influence from organic chemistry was the development of chemical industry, and a chief contributor here was Fischer's teacher, Adolf von Baeyer in Munich, who was awarded the prize in 1905 "in recognition of his services in the advancement of organic chemistry and the chemical industry, ... ." His contributions include, in particular, structure determination of organic dyes (indigo, eosin) and the study of aromatic compounds (terpenes). The third Laureate working in organic chemistry was Otto Wallach in Göttingen, who, like von Baeyer, contributed to alicyclic chemistry, studying not only terpenes but also camphor and other components of ethereal oils. At the award ceremony in 1910 the importance of his discoveries for chemical industry was emphasized.
Two of the early prizes were given for the discovery of new chemical elements. Sir William Ramsay from London received the 1904 Nobel Prize for Chemistry for his discovery of a number of noble gases, a new group of chemically unreactive elements. The first one isolated was argon ("the inactive one"), which Ramsay discovered in 1894, in collaboration with Lord Rayleigh [John William Strutt Rayleigh] of the Royal Institution, who was awarded the Prize for Physics in the same year, his investigations of the density of air and other gases forming the basis for this discovery. The following year Ramsay found helium, observed earlier only in the solar spectrum (hence its name), in emanations from radium, thus anticipating later prizes for nuclear chemistry (see below). Later, in 1898 he also discovered, by fractional distillation of liquid air, neon ("the new one"), krypton ("the hidden one") and xenon ("the strange one"). The isolation of another element, fluorine, by Henri Moissan in Paris was honored with the 1906 Nobel Prize. In attempts to prepare artificial diamonds Moissan had also developed an electric furnace, and this was specifically mentioned in the prize citation, perhaps a reflection of the stipulation in Nobel's will that the Prize for Chemistry can be given "for the most important discovery or improvement".

Ernest Rutherford [Lord Rutherford since 1931], professor of physics in Manchester, was awarded the Nobel Prize for Chemistry in 1908 for his investigations of the chemistry of radioactive substances. The discovery of radioactivity had already been recognized with the Nobel Prize for Physics in 1903, but what Rutherford established was the transformation of one element into another, earlier the alchemist's dream. In his studies of uranium disintegration he found two types of radiation, named - and -rays, and by their deviation in electric and magnetic fields he could show that -rays consist of positively charged particles. His demonstration that these particles are helium nuclei came in the same year as he received the Nobel Prize. Even if the importance of Rutherford's work for chemistry is obvious, he naturally had also received many nominations for the Nobel Prize for Physics (see Section 1).

In 1897 Eduard Buchner, at the time professor in Tübingen, published results demonstrating that the fermentation of sugar to alcohol and carbon dioxide can take place in the absence of yeast cells. Earlier it had generally been considered that living cells possess a "vital force", which makes the life processes possible, even if a few prominent chemists, foremost Jöns Jacob Berzelius and Justus von Liebig, had advocated a chemical basis for life. The vitalistic outlook had been fiercely defended by Louis Pasteur, who maintained that alcoholic fermentation can only occur in the presence of living yeast cells. Buchner's experiments showed unequivocally that fermentation is a catalytic process caused by the action of enzymes, as had been suggested by Berzelius for all life processes, and Buchner called his extract zymase ("enzymes in yeast"). Because of Buchner's experiment, 1897 is generally regarded as the birth date for biochemistry proper. Buchner was awarded the Nobel Prize for Chemistry in 1907, when he was professor at the agricultural college in Berlin. This confirmed the prediction of his former teacher, Adolf von Baeyer: "This will make him famous, in spite of the fact that he lacks talent as a chemist."
 
späť späť   1  |   2  |  3  |  4  |  5  |  ďalej ďalej
 
Zdroje: Westgren, A., Nobel – The Man and His Prizes, ed. Odelberg, W. (Elsevier, New York, 1972), pp. 279-385., Kormos Barkan, D., Walther Nernst and the Transition in Modern Physical Science, (Cambridge University Press, 1999)., Rife, P., Lise Meitner and the Dawn of the Nuclear Age, (Birkhäuser, 1999).
Copyright © 1999-2019 News and Media Holding, a.s.
Všetky práva vyhradené. Publikovanie alebo šírenie obsahu je zakázané bez predchádzajúceho súhlasu.