Dulong, Pierre-Louis

Dulong, Pierre-Louis. Recherches sur la decomposition mutuelle des sels insolubles et des sels solubles. Annales de chimie 82, 1812, 275-308. 

Dulong Pierre-Louis (1785-1838) Fr. chem., research on refractive indices and specific heats of gases, co-formulated Dulong-Petit s law, devised empirical formula for the heat Earnest Charles Mansfield (1941-) US chem., expert in geoscience and minerals (book Thermal analysis of clays 1984) Einstein Albert (1879-1955) Ger. phys., originator of theories of relativity, laws of motion and rest, simultaneity and... 

Research by the French natural philosophers Joseph-Louis Gay-Lussac and Pierre-Louis Dulong during the early 19 century supported the new atomic theory. That work was done in the laboratory of Claude-Louis Berthollet, the founder of the Societe d Arcueil, near Paris. Berthollet s home is shown in Figure 3. The site of the home today is marked by a plaque, shown in Figure 4. A bust of Berthollet can be found in Arcueil s city hall, the Centre Marius Sidobore. Arcueil itself lies just south of the Boulevard Peripherique that rings Paris. 

NC13 can be obtained by chlorination of aqueous solutions containing ammonium ions. NC13 compound was first obtained by Pierre Louis Dulong (1785 -1838) by chlorination of ammonium chloride solutions. Dulong was seriously injured by several explosions of liquid NC13. (ref. 5)... 

Calorimetric studies of the type done by Lavoisier and Laplace (Figure 212) were continued by others including Pierre Louis Dulong (1785-1838) and Alexis Therese Petit (1791-1820). They discovered the law that bears their names the product of the specific heat and the atomic weight of solid elements (e.g., lead, gold, tin, silver, and sulfur) is constant. This really implies that all atoms (independent of their identities) have the same capacity for heat. This result was later extended to solid compounds and ultimately cleared up confusions such as whether the binary oxides of copper were really CuO and CUO2 or CU2O and CuO. 

Dulong and Petit s law /doo-long and pe-teez / The molar thermal capacity of a solid element is approximately equal to 3R, where R is the gas constant (25 J moh ). The law applies only to elements with simple crystal structures at normal temperatures. At lower temperatures the molar heat capacity falls with decreasing temperature (it is proportional to T ). Molar thermal capacity was formerly called atomic heat - the product of the atomic weight (relative atomic mass) and the specific thermal capacity. The law is named for the French physicists Pierre-Louis Dulong (1785-1838) and Alexis-Therese Petit (1791-1820). 

Pierre Louis Dulong bom Feb. 12, 1785, in Rouen, France, died Jul. 18, 1838, in Paris. 

Fortunately, there were other keys to correctness in atomic weights. In 1818, for instance, a French chemist, Pierre Louis Dulong (1785-1838), and a French physicist, Alexis Therese Petit (1791-1820), working in collaboration, found one of them. They discovered that the specific heat of elements (the temperature rise that follows upon the absorption of a fixed quantity of heat) seemed to vary inversely with the atomic weight. That is, if element x had twice the atomic weight of element y, the temperature of element x would rise by only half as many... 

Two major developments then followed that permitted better atomic weight determinations. They were the law of Pierre-Louis Dulong and Alexis-Therese Petit and the law of isomorphism. 

Stanislao Cannizzaro s method for determining atomic weights was not easy to apply to the metallic elements, as it required volatile compounds. Instead, other methods continued to be used for metals. One important way of obtaining atomic weights was through the 1819 law of Pierre-Louis Dulong and Alexis-Therese Petit. As discussed in chapter 2, these authors had found an approximate relationship between the specific heat and atomic weight of a sohd element to be ... 

Dulong-Petit law A chemical law proposed in 1819 by French physicists and chemists Pierre Louis Dulong and Alexis Therese Petit stating the classical expression for the specific... 

Berzelius also used the law of Pierre Louis Dulong (1785-1838) and Alexis Therese Petit (1791-1820). These two Frenchmen noticed in 1819 that for a number of elements the product of the atomic weight and specific heat (the atomic heat) was constant. They had hoped that this would provide an accurate method of determining atomic weights, but the constancy of atomic heats proved to be only approximate. However, Berzelius was able to use this approximate constancy to confirm the formula MO for the oxides of several metals (e.g. Mg, Ca, Ba) in preference to the formula MO2 which he had used earlier. 

French chemists Pierre-Louis Dulong and Alexis Therese... 

Pierre Louis Dulong, professor at the ficole Polytechnique, wrote on July F, 1826, in a letter to Berzelius in Stockholm (cited from Mary Weeks) ... 

Pierre Louis Dulong, 1785-1838, was a French chemist originally trained as a physician. Alexis Therdse Petit, 1791-1820, was a French physicist. 

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