Robert Bunsen

Robert Wilhelm Eberhard Bunsen ( born March 30, 1811 in Göttingen; † August 16, 1899 in Heidelberg ) was a German chemist.

He developed along with Gustav Robert Kirchhoff, the spectral analysis with the aid of chemical elements can be detected with high specificity. He perfected the eponymous Bunsen burners and invented the Bunsen element and the Bunsen photometer.

Life

Early years

Robert Bunsen was born as the youngest of four sons of Göttingen literature professor and librarian Christian Bunsen in Göttingen. In the literature there are different information about his exact date of birth: While Bunsen's baptismal record and a handwritten written CV refer to the March 30, 1811, several reference books call March 31, at the Bunsen according to his biographer Georg Lockemann in later years, his Birthday celebrated. His grandfather was Philip Christian Bunsen. After leaving school in Göttingen and graduating from high school in Holzminden he studied natural sciences, particularly chemistry and mathematics at the University of Göttingen. He made 1830 a dissertation Enumeratio ac descriptio hygrometrorum quae inde a saussurii Temporibus proposita sunt about hygrometers and in 1831 received his doctorate. From 1832 to 1833 he traveled with a grant from the provincial government through western Europe to educate yourself. During this time he learned Fried Ferdinand Runge, Justus Liebig in Giessen and know Eilhard Mitscherlich in Berlin. He and the sons of his godfather made ​​themselves unpopular with the Frankfurter guard tower.

Göttingen

After his return to Bunsen 1834 Habilitation in Göttingen and began experimental studies of the (in ) solubility of metal salts of arsenic acid. Even today, his discovery of the hydrous iron oxide is used as an antidote to arsenic poisoning. After the death of Friedrich Stromeyer (1835 ) and before the appointment of Friedrich Wöhler (1836 ) Bunsen became the representative of the Department.

Kassel

In 1836, Bunsen succeeded Friedrich Wöhler at the Higher Commercial School ( Polytechnic ) in Kassel. Here he began the study of cacodyl compounds ( Tetramethyldiarsan As2 ( CH3) 4 and descendants ), where he was injured in 1836 by a violent explosion in the right eye and partially blind. 1838 took Bunsen basic physical and chemical studies of the processes taking place in the blast furnace processes located ( eg blast furnace gas) in the north of Kassel in Veckerhagen, then important ironworks.

Marburg

1839 Bunsen was transferred to the University of Marburg, where he continued his work on the cacodyl compounds and the development of gas- analytical methods. His work brought him quick and wide recognition. 1841 Bunsen developed a zinc -carbon battery ( Bunsen element ), which was reasonably priced and versatile.

As in 1845, the Icelandic volcano Hekla erupted again, he was invited by the Danish government for an expedition to Iceland. After his cousin Robert Louis Charles Bunsen, physician to the Elector in Kassel, the Elector Frederick William was able to convince, 1846, he received six months' leave. The analysis of gas and rock samples brought claiming him in the next six years, and he succeeded in expanding the gas analysis to an exact method. Significant students were in Marburg: Hermann Kolbe, Edward Frankland, John Tyndall, Heinrich Debus.

Breslau

1850 Bunsen took a professorship at the University of Breslau. Here they built him a new laboratory, and here he met the physicist Gustav Robert Kirchhoff know. But Bunsen worked in Breslau only three semesters.

Heidelberg

1852 Bunsen took the chair of Leopold Gmelin at Heidelberg University. Again, he got a new laboratory ( with service apartment). With nitric acid it was able to produce pure metals such as chromium, magnesium, aluminum, manganese, sodium, barium, calcium and lithium by electrolysis. In his collaboration with Sir Henry Roscoe from 1852 to the light- induced formation of hydrogen chloride from hydrogen and chlorine was studied.

After seven years of Bunsen broke in 1859 working with Roscoe and worked together with Kirchhoff on the spectral analysis of chemical elements. By means of spectroscopy, the characteristic spectral lines were investigated in the heating of chemical substances in the flame. For this purpose, Bunsen perfected a special gas burner, which had previously been invented by Michael Faraday and was later given the name of Bunsen.

In the spectral analysis of the mineral water of the newly developed Maxquelle in Bunsen and Kirchhoff discovered Durkheim 1860/61, the alkali metals cesium and rubidium. Through their studies, it was also possible to explain the Fraunhofer lines and thus to lay one of the essential foundations for modern astronomy.

A manuscript of his assistants to prepare the experiments and the Tafelanschriebs for the course " Experimental Chemistry " appeared after 145 years in California. Prof. Inge King, a descendant of that wizard, handed the manuscript at the annual celebration of the University of Heidelberg in 2004 at the Faculty of Chemical (now in the archives of the Bunsen Society ). Interesting detail: The recorded period system at that time consisted of 60 elements, cesium and rubidium were before then grudge with pencil. Significant students were in Heidelberg: Konrad Beilstein, Emil Erlenmeyer, Henry Roscoe, Ludwig Carius, Lothar Meyer, Hans Landolt, Adolf loved ones, Adolf von Baeyer, Carl Graebe, Albert Ladenburg, Hermann Wichelhaus, Viktor Meyer, Hans Bunte.

Age

When Bunsen retired at the age of 78 years, he devoted himself to geology, which he had operated until then only as a hobby. On August 16, 1899, he died at the age of 88 years in Heidelberg. His grave is located at the Heidelberg hill cemetery in the department: (V new 25). In his obituary Roscoe said:

"As to investigator, he was great. As a teacher, even Greater. As a man and friend, hey what greatest. "

" As a researcher, he was great. As a teacher, even great. As a man and friend he was the greatest. "

Honors and Memberships

Scientific work

In Göttingen Bunsen performed his first work on the cyanogen.

In 1846 Bunsen received by the Danish Government 's invitation to accompany an expedition to Iceland. In Iceland, he examines the geyser. He finds in the exiting gases hydrogen, hydrogen sulfide and carbon dioxide. For the occurrence of hydrogen, he finds the explanation of the decomposition of hydrogen sulphide into sulfur and hydrogen. Igneous rocks and feldspars from Iceland Bunsen examined in relation to their chemical composition.

In Kassel he examined organic arsenic compounds and the blast furnace process. In his first work on furnaces Bunsen found that 75 % of the heating value of the coal was not used. In England Bunsen made ​​in 1847 with Playfair studies on English blast furnaces. He noted that were used only 20% of carbon monoxide for the reduction process and the majority escapes unused from the blast furnace. He made proposals such as the heat could be better used. His studies led to an improvement in combustion technology and the use of producer gas in the blast furnace process. Between 1837 and 1843 he studied the organic arsenic compound cacodyl ( Tetramethyldiarsan As2 (CH3 ) 4). The connection was then quite important, since the molecular mass and the inorganic- organic nature of the compound was by gas density measurements prove.

He developed the Iodometry to a quantitative determination method.

Bunsen developed the Bunsen burner, which was initially operated with city gas and of an admixture of oxygen. In the lower part of the flame cone, he could reduce the sample mineral salt (e.g., bismuth salt to elemental bismuth ), in the upper part of the flame, the sample was oxidized ( bismuth salt white bismuth ).

Furthermore, Bunsen, the first low-priced power source, zinc-carbon element designed for laboratory use. The invention was based on work done by Cooper ( London) and Schönbein that the platinum replaced the zinc -platinum element for the first time by low-cost coal. Bunsen improved the element of the preparation of the coal and the particular arrangement. The element was until the discovery of the principle of electrodynamics by Werner von Siemens, the most common element to generate electricity. With the electrolytic deposition Bunsen and staff won the elements magnesium, lithium, calcium, aluminum from molten chlorides. In his laboratory discovered by Bunsen elements cesium and rubidium were of Settenberg isolated by electrolysis.

Significant was his book gasometric analyzes, Friedrich Vieweg Verlag 1857 ( 1877). In the book, for example, methods for isolation of gases in glass vessels, provisions of the ingredients of gases, correction of Graham 's theory of gas diffusion, temperatures of flames were.

Another very important work was the study of the chemical action of light. Bunsen disassembled the light with a prism and studied the effect of the light disassembled radiation on chemical reactions, plant growth, worrying made ​​for light energy between the equator and the Arctic Circle.

As early as 1826 William Henry Fox Talbot had made ​​attempts to spectral analysis. In 1860, Bunsen and Gustav Robert Kirchhoff published their work on the applicability of spectral analysis. The spectroscope consisted of a prism with two lenses and an ocular in a wooden box. The prism disassembled the uniform white light into a spectrum. Brought you a salt sample in a Bunsen burner flame ( a candle flame did not give good results ), the spectroscope for each element showed very characteristic color lines ( Emissisionsspektren ) at certain points of the spectrum. With the spectroscope of alkali and alkaline earth salts, indium, thallium, hydrogen could be detected.

By spectroscope by Bunsen and Kirchhoff were two new chemical elements are found: rubidium and cesium. The determination of elements - even the smallest traces - in a substance sample was easily possible from now on. The chemical composition of the star was demonstrated by the work of Kirchhoff due to the absorption spectra.

In 1870 Bunsen developed the ice calorimeter. With the calorimeter Bunsen could determine the specific heat of substances. The investigation led to a more accurate determination of the atomic weight of indium.

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