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Jean Baptiste André Dumas (French pronunciation: [ʒɑ̃ batist ɑ̃dʁe dyma]; 14 July 1800 – 10 April 1884) was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights (relative atomic masses) and molecular weights by measuring vapor densities.
Jean-Baptiste Dumas used the terms "physical atoms" and "chemical atoms"; a "physical atom" was a particle that cannot be divided by physical means such as temperature and pressure, and a "chemical atom" was a particle that could not be divided by chemical reactions. [26]
The Dumas method of molecular weight determination was historically a procedure used to determine the molecular weight of an unknown volatile substance. [ 1 ] [ 2 ] The method was designed by the French chemist Jean Baptiste André Dumas , after whom the procedure is now named.
With the rise of scholasticism and the decline of the Roman Empire, the atomic theory was abandoned for many ages in favor of the various four element theories and later alchemical theories. The 17th century, however, saw a resurgence in the atomic theory primarily through the works of Gassendi, and Newton.
Jean-Baptiste Dumas "For his late valuable researches in organic chemistry, particularly those contained in a series of memoirs on chemical types and the doctrine of substitution, and also for his elaborate investigations of the atomic weights of carbon, oxygen, hydrogen, nitrogen and other elements" — 1844: Carlo Matteucci
Jean-Baptiste Lamarck (1744–1829) – French naturalist, biologist and academic whose theories on evolution preceded those of Darwin; Johann von Lamont (1805–1879) – astronomer and physicist who studied the magnetism of the Earth and was the first to calculate the mass of Uranus
Chloromethane (originally called "chlorohydrate of methylene") was among the earliest organochlorine compounds to be discovered when it was synthesized by French chemists Jean-Baptiste Dumas and Eugène-Melchior Péligot in 1835 by boiling a mixture of methanol, sulfuric acid, and sodium chloride. [15]
This insight led to the development of structural theories, such as the radical theory of Jean-Baptiste Dumas and the substitution theory of Auguste Laurent. [152] [153] A definitive structure theory was proposed in 1858 by August Kekulé, who suggested that carbon is tetravalent and can bond to itself, forming chains found in natural products.