Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom. The term isotope is formed from the Greek roots isos (ἴσος "equal") and topos (τόπος "place"), meaning "the same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same position on the periodic table. It was coined by a Scottish doctor and writer Margaret Todd in 1913 in a suggestion to chemist Frederick Soddy.
Introduction
Isotope
Isotope | Introduction
They are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number O, O, and O Oxygen-16, Oxygen-17 and Oxygen-18. Three stable isotopes, O, O, and O.
oxygen (o2) is formed in photosynthesis as a direct result of
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Light-driven splitting of water during oxygenic photosynthesis
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how does lavoisier contribute?
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He conducted the first adequate quantitative experiments on oxidation and gave the first correct explanation of how combustion works
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what are its isotopes?
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Lavoisier conducted the first adequate quantitative experiments on oxidation and gave the first correct explanation of how combustion works. He used these and similar experiments, all started in 1774, to discredit the phlogiston theory and to prove that the substance discovered by Priestley and Scheele was a chemical element. In one experiment, Lavoisier observed that there was no overall increase in weight when tin and air were heated in a closed container. He noted that air rushed in when he opened the container, which indicated that part of the trapped air had been consumed. He also noted that the tin had increased in weight and that increase was the same as the weight of the air that rushed back in.
Oxygen | Lavoisier's contribution
Lavoisier's fundamental contributions to chemistry were a result of a conscious effort to fit all experiments into the framework of a single theory. He established the consistent use of the chemical balance, used oxygen to overthrow the phlogiston theory, and developed a new system of chemical nomenclature which held that oxygen was an essential constituent of all acids (which later turned out to be erroneous). Lavoisier also did early research in physical chemistry and thermodynamics in joint experiments with Laplace. They used a calorimeter to estimate the heat evolved per unit of carbon dioxide produced, eventually finding the same ratio for a flame and animals, indicating that animals produced energy by a type of combustion reaction.
Antoine Lavoisier | Legacy
During late 1772 Lavoisier turned his attention to the phenomenon of combustion, the topic on which he was to make his most significant contribution to science. He reported the results of his first experiments on combustion in a note to the Academy on 20 October, in which he reported that when phosphorus burned, it combined with a large quantity of air to produce acid spirit of phosphorus, and that the phosphorus increased in weight on burning. In a second sealed note deposited with the Academy a few weeks later (1 November) Lavoisier extended his observations and conclusions to the burning of sulfur and went on to add that "what is observed in the combustion of sulfur and phosphorus may well take place in the case of all substances that gain in weight by combustion and calcination: and I am persuaded that the increase in weight of metallic calces is due to the same cause."
Antoine Lavoisier | Oxygen theory of combustion
Lavoisier concluded, "La respiration est donc une combustion," That is, respiratory gas exchange is combustion, like that of burning a candle. Lavoisier was the first to conclude by experiment that the Law of Conservation of Mass applied to chemical change. His hypothesis was that the mass of the reactants would be the same as the mass of the products in a chemical reaction. He experimented on vinous fermentation, determining the amounts of hydrogen, oxygen, and carbon in sugar. Weighing a quantity of sugar, he added yeast and water in measured amounts, allowing the mixture to ferment. Lavoisier then measured the mass of the carbonic acid gas and water that were given off during fermentation and weighed the residual liquor, the components of which were then separated and analyzed to determine their elementary composition.
History of experiments | Antoine Lavoisier
In this way he controlled a couple of potential confounding factors. He was able to capture the carbonic acid gas and water vapor that were given off during fermentation so that his final measurements would be as accurate as possible. Lavoisier concluded that the total mass of the reactants was equal to the mass of the final product and residue. Moreover, he showed that the total mass of each constituent element before and after the chemical change remained the same. Similarly, he demonstrated via experimentation that the mass of products of combustion is equal to the mass of the reacting ingredients.
History of experiments | Antoine Lavoisier
Lavoisier produced hydrogen for his experiments on mass conservation by reacting a flux of steam with metallic iron through an incandescent iron tube heated in a fire. Anaerobic oxidation of iron by the protons of water at high temperature can be schematically represented by the set of following reactions: Many metals such as zirconium undergo a similar reaction with water leading to the production of hydrogen.
Hydrogen | Discovery and use
The center compartment held the source of heat, in this case the guinea pig or piece of burning charcoal. The middle compartment held a specific amount of ice for the heat source to melt. The outside compartment contained packed snow for insulation. Lavoisier then measured the quantity of carbon dioxide and the quantity of heat produced by confining a live guinea pig in this apparatus. Lavoisier also measured the heat and carbon dioxide produced when burning a piece of charcoal in the calorimeter. Using this data, he concluded that respiration was in fact a slow combustion process. He also discovered through precise measurements that these processes produced carbon dioxide and heat with the same constant of proportionality.
History of experiments | Antoine Lavoisier
Lavoisier demonstrated that organisms disassemble and reconstitute atmospheric air in the same manner as a burning body. With Pierre-Simon Laplace, Lavoisier used a calorimeter to estimate the heat evolved per unit of carbon dioxide produced. They found the same ratio for a flame and animals, indicating that animals produced energy by a type of combustion. Lavoisier believed in the radical theory, which stated that radicals, which function as a single group in a chemical reaction, would combine with oxygen in reactions. He believed all acids contained oxygen. He also discovered that diamond is a crystalline form of carbon.
History of chemistry | Antoine-Laurent de Lavoisier
He found that for 224 grains of "fixed air" (CO) produced, . of ice was melted in the calorimeter. Converting grains to grams and using the energy required to melt . of ice, one can compute that for each gram of CO produced, about 2.02 kcal of energy was produced by the combustion of carbon or by respiration in Lavoisier's calorimeter experiments. This compares well with the modern published heat of combustion for carbon of 2.13 kcal/g. This continuous slow combustion, which Lavoisier and Laplace supposed took place in the lungs, enabled the living animal to maintain its body temperature above that of its surroundings, thus accounting for the puzzling phenomenon of animal heat.
History of experiments | Antoine Lavoisier
This and other experiments on combustion were documented in his book "Sur la combustion en général", which was published in 1777. In that work, he proved that air is a mixture of two gases; 'vital air', which is essential to combustion and respiration, and "azote" (Gk. "" "lifeless"), which did not support either. "Azote" later became "nitrogen" in English, although it has kept the earlier name in French and several other European languages. Lavoisier renamed 'vital air' to "oxygène" in 1777 from the Greek roots " (oxys)" (acid, literally "sharp", from the taste of acids) and "-γενής (-genēs)" (producer, literally begetter), because he mistakenly believed that oxygen was a constituent of all acids.
Oxygen | Lavoisier's contribution
The same year he coined the name oxygen for this constituent of the air, from the Greek words meaning "acid former". He was struck by the fact that the combustion products of such nonmetals as sulfur, phosphorus, charcoal, and nitrogen were acidic. He held that all acids contained oxygen and that oxygen was therefore the acidifying principle.
Antoine Lavoisier | Easter memoir
Chemists (such as Sir Humphry Davy in 1812) eventually determined that Lavoisier was wrong in this regard (hydrogen forms the basis for acid chemistry), but by then the name was too well established.
Oxygen | Lavoisier's contribution
The outer shell of the calorimeter was packed with snow, which melted to maintain a constant temperature of around an inner shell filled with ice. By measuring the quantity of carbon dioxide and heat produced by confining a live guinea pig in this apparatus, and by comparing the amount of heat produced when sufficient carbon was burned in the ice calorimeter to produce the same amount of carbon dioxide as that which the guinea pig exhaled, they concluded that respiration was, in fact, a slow combustion process. Lavoisier stated, ""la respiration est donc une combustion,"" that is, respiratory gas exchange is a combustion, like that of a candle burning.
Antoine Lavoisier | Physiological work
During his two-year postdoctoral fellowship at Stanford, he set up the first direct simulations of turbulent flames. These first academic simulations paved the way for numerical simulation tools for real combustion chambers which use the largest computers available today and are used to calculate French aeronautical combustion chambers (rockets, helicopters, aircraft, furnaces). In addition to this numerical simulation work, he has also developed theoretical and experimental activities on combustion at the IMFT.
Thierry Poinsot | Scientific contributions
This time he measured the mass of the air surrounding the experiment as well. He discovered that the mass gained in the product was lost from the air. These experiments provided further support for his Law of Conservation of Mass. One of Lavoisier's experiments connected the worlds of respiration and combustion. Lavoisier's hypothesis was that combustion and respiration were one and the same, and combustion occurs with every instance of respiration. Working with Pierre-Simon Laplace, Lavoisier designed an ice calorimeter apparatus for measuring the amount of heat given off during combustion or respiration. This machine consisted of three concentric compartments.
History of experiments | Antoine Lavoisier
He examined the different processes by which they were obtaining isotopes. By the end of the summer in 1940, Peierls preferred gaseous diffusion to thermal diffusion.
MAUD Committee | University of Birmingham
The relationship between combustion and respiration had long been recognized from the essential role which air played in both processes. Lavoisier was almost obliged, therefore, to extend his new theory of combustion to include the area of respiration physiology. His first memoirs on this topic were read to the Academy of Sciences in 1777, but his most significant contribution to this field was made in the winter of 1782/1783 in association with Laplace. The result of this work was published in a memoir, "On Heat." Lavoisier and Laplace designed an ice calorimeter apparatus for measuring the amount of heat given off during combustion or respiration.
Antoine Lavoisier | Physiological work
Antoine-Laurent de Lavoisier demonstrated with careful measurements that transmutation of water to earth was not possible, but that the sediment observed from boiling water came from the container. He burnt phosphorus and sulfur in air, and proved that the products weighed more than the original samples, with the mass gained being lost from the air. Thus, in 1789, he established the Law of Conservation of Mass, which is also called "Lavoisier's Law." Repeating the experiments of Priestley, he demonstrated that air is composed of two parts, one of which combines with metals to form calxes. In "Considérations Générales sur la Nature des Acides" (1778), he demonstrated that the "air" responsible for combustion was also the source of acidity.
History of chemistry | Antoine-Laurent de Lavoisier
Paulze accompanied Lavoisier in his lab during the day, making entries into his lab notebooks and sketching diagrams of his experimental designs. The training she had received from the painter Jacques-Louis David allowed her to accurately and precisely draw experimental apparatuses, which ultimately helped many of Lavoisier's contemporaries to understand his methods and results. Furthermore, she served as the editor of his reports. Together, the Lavoisiers rebuilt the field of chemistry, which had its roots in alchemy and at the time was a convoluted science dominated by George Stahl’s theory of phlogiston. In the eighteenth century, the idea of phlogiston (a fire-like element which is gained or released during a material's combustion) was used to describe the apparent property changes that substances exhibited when burned.
Marie-Anne Paulze Lavoisier | Contributions to chemistry
After the war, Urey became professor of chemistry at the Institute for Nuclear Studies, and then became Ryerson professor of chemistry at the University of Chicago in 1952. He did not continue his pre-war research with isotopes. However, applying the knowledge gained with hydrogen to oxygen, he realized that the fractionation between carbonate and water for oxygen-18 and oxygen-16 would decrease by a factor of 1.04 between . The ratio of the isotopes could then be used to determine average temperatures, assuming that the measurement equipment was sufficiently sensitive. The team included his colleague Ralph Buchsbaum. Examination of a 100-million-year-old belemnite then indicated the summer and winter temperatures that it had lived through over a period of four years.
Harold Urey | Post-war years
"Having calculated all the lime in oats fed to a hen, found still more in the shells of its eggs. Therefore, there is a creation of matter. In that way, no one knows."
Louis Nicolas Vauquelin | Contributions to chemistry
Combustion analysis of the mixture of deuterated and undeuterated 1,2-dimethylpyrrolidines gave the value of 0.78 atom of deuterium per molecule, which corresponds to an isotope effect ("k"/"k") of 3.54. The value of the isotope effect was verified by an independent method of deuterium analysis which relied on the comparison of the intensity of the C-D stretching absorptions in the infrared spectra of mixed 1,2-dimethylpyrrolidines from the cyclization of 10 with the pure sample of 1,2-dimethylpyrrolidine-2-"d" 12; the IR-based analysis produced "k"/"k" of 3.42, which is in agreement with the combustion analysis. Studies performed to determine "k"/"k" for cyclization to a primary carbon also gave "k"/"k"»1, which strongly suggested that the breaking of the C-H bond proceeds to a rather considerable extent in the transition state.
Hofmann–Löffler reaction | Mechanistic studies
The laboratory at the University of Birmingham was responsible for all the theoretical work, such as what size of critical mass was needed for an explosion. It was run by Peierls, with the help of fellow German refugee scientist Klaus Fuchs. The laboratories at the University of Liverpool and the University of Oxford experimented with different types of isotope separation. Chadwick's group at Liverpool dealt with thermal diffusion, which worked based on the principle that different isotopes of uranium diffuse at different speeds because of the equipartition theorem. Franz Simon's group at Oxford investigated the gaseous diffusion of isotopes. This method works on the principle that at differing pressures uranium 235 would diffuse through a barrier faster than uranium 238.
Tube Alloys | MAUD Committee
Lavoisier also contributed to early ideas on composition and chemical changes by stating the radical theory, believing that radicals, which function as a single group in a chemical process, combine with oxygen in reactions. He also introduced the possibility of allotropy in chemical elements when he discovered that diamond is a crystalline form of carbon.
Antoine Lavoisier | Legacy
Antoine Lavoisier, one of the pioneers in these early insights, stated that "Nothing is lost, nothing is created, everything is transformed", which would later be known as the law of conservation of mass. Lavoisier used the experimental fact that some metals gained mass when they burned to support his ideas.
Combustibility and flammability | Introduction
The quasi-equilibrium produces radioactive isobars Ti, Cr, Fe, and Ni, which (except Ti) are created in abundance but decay after the explosion and leave the most stable isotope of the corresponding element at the same atomic weight. The most abundant and extant isotopes of elements produced in this way are Ti, Cr, and Fe. These decays are accompanied by the emission of gamma-rays (radiation from the nucleus), whose spectroscopic lines can be used to identify the isotope created by the decay. The detection of these emission lines were an important early product of gamma-ray astronomy.
Nucleosynthesis | Explosive nucleosynthesis
He began his thesis in 1975 in the CEA Saclay under the direction of Marc Javoy and Liliane Merlivat and edited by Samuel Epstein at Caltech, Pasadena, California. He joined the CNRS in 1980 at the Laboratory of stable isotope geochemistry at the University of Jussieu, where he defended his thesis on the isotopic compositions (H, C, N) of carbonaceous meteorites in 1982. Between 1983 and 1990, he worked successively with Liliane Merlivat in Saclay, Samuel Epstein at the California Institute of Technology and Marc Javoy at Jussieu. In 1990 he became a Directeur de Recherche in the CNRS. In 1992 he worked for a few months in Thiruvananthapuram, India, where he created a laboratory for isotopic analysis.
François Robert | Career
Paulze contributed thirteen drawings that showed all the laboratory instrumentation and equipment used by the Lavoisiers in their experiments. She also kept strict records of the procedures followed, lending validity to the findings Lavoisier published.
Marie-Anne Paulze Lavoisier | Contributions to chemistry
When reduced without charcoal, it gave off an air which supported respiration and combustion in an enhanced way. He concluded that this was just a pure form of common air and that it was the air itself "undivided, without alteration, without decomposition" which combined with metals on calcination. After returning from Paris, Priestley took up once again his investigation of the air from mercury calx. His results now showed that this air was not just an especially pure form of common air but was "five or six times better than common air, for the purpose of respiration, inflammation, and ...
Antoine Lavoisier | Joseph Priestley
The division of the MAUD Committee at Oxford was led by Simon. As a German émigré, he was only able to get involved after Peierls vouched for him, pointing out that Simon had already begun research on isotope separation, which would give the project a head start by his participation. The Oxford team was mostly composed of non-British scientists, including Nicholas Kurti, Kurt Mendelssohn, Heinrich Kuhn, Henry Shull Arms and Heinz London. They concentrated on isotope separation with a method known as gaseous diffusion. This is based on Graham's law, which states that the rate of effusion of a gas through a porous barrier is inversely proportional to the square root of the gas's molecular mass.
MAUD Committee | University of Oxford
In the spring of 1774, Lavoisier carried out experiments on the calcination of tin and lead in sealed vessels, the results of which conclusively confirmed that the increase in weight of metals in combustion was due to combination with air. But the question remained about whether it was in combination with common atmospheric air or with only a part of atmospheric air. In October the English chemist Joseph Priestley visited Paris, where he met Lavoisier and told him of the air which he had produced by heating the red calx of mercury with a burning glass and which had supported combustion with extreme vigor.
Antoine Lavoisier | Joseph Priestley
His work focuses mainly on combustion, fluid mechanics and energy. To do this, he uses experiments and theoretical methods. In addition, he relies on high performance numerical simulation which consists in creating 'virtual' digital twins of real systems (such as an airplane or helicopter engine) thanks to supercomputers now comprising several million processors (see Top500). After his PhD thesis on the physical mechanisms controlling the cooking of tyres (for Michelin), he developed experimental and theoretical studies of combustion instabilities and their control in aeronautical engines under the direction of Sébastien Candel at the EM2C laboratory at Centrale Paris. He has also developed models for turbulent combustion.
Thierry Poinsot | Scientific contributions
His academic contributions include: Candel was also Vice President of the "Combustion Institute" from 1996 to 2002, and Associate Editor for "Combustion and Flame" from 2001 to 2008.
Sébastien Candel | Contributions
His major works were studies about phosphoric ether, pyrocitric acid, pyro acids of the malic acid, chromium salts, and compounds of iodine. Lassaigne also did research on processes for the carbonization of organic matter. Lassaigne discovered new alkaloids and made major investigations related to toxicology of phosphorus and hydrocyanic acid. He also discovered new dyes, and in 1831 won an award by ""Société d'Encouragement de l'Industrie"" (Society for Encouragement of Industry) for his work on the process of enamel elaboration for pottery.
Jean Louis Lassaigne | Contributions and major works
Lavoisier recognized that Black's fixed air was identical with the air evolved when metal calces were reduced with charcoal and even suggested that the air which combined with metals on calcination and increased the weight might be Black's fixed air, that is, CO.
Antoine Lavoisier | Joseph Black's "fixed air"
Johnston was a researcher at the University of California at Berkeley 1925-28 and an associate of cryogenics pioneer William Giauque when his experiments proved the existence of oxygen isotopes with atomic masses 17 and 18. Previously it had been believed that oxygen only existed as O; as atomic masses of other elements were calculated on the basis of 16.0 not 16.0035, this was a significant discovery. The work, published in 1929, also led to the discovery in 1932 of heavy hydrogen (deuterium) by Harold C Urey. Giauque was awarded the 1949 Nobel Prize for chemistry for this work, and did not forget to recognize Johnston's contribution.
Herrick L. Johnston | University of California
Antoine Lavoisier is regarded as the inventor of elemental analysis as a quantitative, experimental tool to assess the chemical composition of a compound. At the time elemental analysis was based on gravimetric determination of specific adsorbant materials before and after selective adsorption of the combustion gases. Today fully automated systems based on thermal conductivity or infrared spectroscopy detection of the combustion gases, or other spectroscopic methods are used.
Elemental analysis | History
Antoine-Laurent de Lavoisier ( , , ; 26 August 17438 May 1794), also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology. He is widely considered in popular literature as the "father of modern chemistry". It is generally accepted that Lavoisier's great accomplishments in chemistry stem largely from his changing the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion.
Antoine Lavoisier | Introduction
This showed the details of the oxidation process that was corroding the image.
View from the Window at Le Gras | Scientific analysis and conservation
First of all isotope labeling using deuterium confirms the regiochemistry of the addition:
Hydrogenation | Thermodynamics and mechanism
Lavoisier's researches included some of the first truly quantitative chemical experiments. He carefully weighed the reactants and products of a chemical reaction in a sealed glass vessel so that no gases could escape, which was a crucial step in the advancement of chemistry. In 1774, he showed that, although matter can change its state in a chemical reaction, the total mass of matter is the same at the end as at the beginning of every chemical change. Thus, for instance, if a piece of wood is burned to ashes, the total mass remains unchanged if gaseous reactants and products are included.
Antoine Lavoisier | Pioneer of stoichiometry
The experiments of Antoine Lavoisier (1743–1794), a French chemist regarded as the founder of modern chemistry, were among the first to be truly quantitative. Lavoisier showed that although matter changes its state in a chemical reaction, the quantity of matter is the same at the end as at the beginning of every chemical reaction. In one experiment, he burned phosphorus and sulfur in air to see whether the results further supported his previous conclusion (Law of Conservation of Mass). In this experiment, however, he determined that the products weighed more than the original phosphorus and sulfur. He decided to do the experiment again.
History of experiments | Antoine Lavoisier
Priestley at this time was unsure of the nature of this gas, but he felt that it was an especially pure form of common air. Lavoisier carried out his own researches on this peculiar substance. The result was his memoir "On the Nature of the Principle Which Combines with Metals during Their Calcination and Increases Their Weight", read to the Academy on 26 April 1775 (commonly referred to as the Easter Memoir). In the original memoir Lavoisier showed that the mercury calx was a true metallic calx in that it could be reduced with charcoal, giving off Black's fixed air in the process.
Antoine Lavoisier | Joseph Priestley
They also made a study of the latent heat of fusion of ice, and a careful investigation of the range of applicability of the Dulong-Petit law representing the law of cooling.
Paul-Quentin Desains | Introduction
His non-isotope work has included discovery of an unknown source of the greenhouse gas nitrous oxide that lead the global industrial elimination of all emissions, a major contribution to changing global climate change. Thiemens has worked on developing new imaging techniques for space mission return samples and detection of superconductivity in nature.
Mark H. Thiemens | Introduction
Lavoisier's chemical research between 1772 and 1778 was largely concerned with developing his own new theory of combustion. In 1783 he read to the academy his paper entitled "Réflexions sur le phlogistique" (Reflections on Phlogiston), a full-scale attack on the current phlogiston theory of combustion. That year Lavoisier also began a series of experiments on the composition of water which were to prove an important capstone to his combustion theory and win many converts to it. Many investigators had been experimenting with the combination of Henry Cavendish's inflammable air, which Lavoisier termed hydrogen (Greek for "water-former"), with "dephlogisticated air" (air in the process of combustion, now known to be oxygen) by electrically sparking mixtures of the gases.
Antoine Lavoisier | Dismantling phlogiston theory
That this can be used as a means of isotope separation was first demonstrated by Klaus Clusius and Gerhard Dickel in Germany in 1938, who used it to separate isotopes of neon. They used an apparatus called a "column", consisting of a vertical tube with a hot wire down the centre. The advantage of the technique was that it was simple in design and there were no moving parts. But it could take months to reach equilibrium, required a lot of energy, and needed high temperatures that could cause a problem with the uranium hexafluoride. Another line of research at Liverpool was measuring the fission cross section of uranium-235, on which Frisch and Peierls' calculations depended.
MAUD Committee | University of Liverpool
Rubens said that he would be happy for her to work in his laboratory. He also added that Otto Hahn at the chemistry institute was looking for a physicist to collaborate with. A few minutes later she was introduced to Hahn. He had studied radioactive substances under Sir William Ramsay, and in Montreal under Rutherford, and was already credited with the discovery of what were then thought to be several new radioactive elements. (In fact, they were isotopes of known elements, but the concept of an isotope, along with the term, was only propounded by Frederick Soddy in 1913.) Hahn was the same age as herself, and she noted his informal and approachable manner.
Lise Meitner | Friedrich Wilhelm University
He recognized and named oxygen (1778) and hydrogen (1783), and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787) and was also the first to establish that sulfur was an element (1777) rather than a compound. He discovered that, although matter may change its form or shape, its mass always remains the same. Lavoisier was a powerful member of a number of aristocratic councils, and an administrator of the "Ferme générale". The "Ferme générale" was one of the most hated components of the "Ancien Régime" because of the profits it took at the expense of the state, the secrecy of the terms of its contracts, and the violence of its armed agents.
Antoine Lavoisier | Introduction
Charles Bernard Desormes (; 3 June 1777 – 30 August 1862) was a French physicist and chemist. He determined the ratio of the specific heats of gases in 1819. He did this and almost all his scientific work in collaboration with his son-in-law Nicolas Clément (1779–1841). Clément and Desormes correctly determined the composition of carbon disulfide (CS) and carbon monoxide (CO) in 1801–02. In 1806 they elucidated all the chemical reactions that take place during the production of sulfuric acid by the lead chamber method, as used in industrial chemistry. In 1813 they made a study of iodine and its compounds.
Charles Bernard Desormes | Introduction
Octave Leopold Boudouard became a professor at the Conservatoire National des Arts et Métiers in Paris. He worked in various fields of applied chemistry, such as the chemistry of fuels and clays. His most important work was his research into chemical equilibria when reducing iron oxides in a blast furnace. In 1901 he proposed the first theory of the hydrogenation of carbon monoxide, where he considered that metal oxide was reacting with carbon. In 1905 Boudouard identified the Boudouard reaction, where carbon and carbon dioxide combine to form carbon monoxide at high temperatures, while the reverse occurs at lower temperatures.
Octave Boudouard | Career
This was an invaluable service to Lavoisier, who relied on Paulze's translation of foreign works to keep abreast of current developments in chemistry. In the case of phlogiston, it was Paulze's translation that convinced him the idea was incorrect, ultimately leading to his studies of combustion and his discovery of oxygen gas. Paulze was also instrumental in the 1789 publication of Lavoisier's Elementary Treatise on Chemistry, which presented a unified view of chemistry as a field. This work proved pivotal in the progression of chemistry, as it presented the idea of conservation of mass as well as a list of elements and a new system for chemical nomenclature.
Marie-Anne Paulze Lavoisier | Contributions to chemistry
Le Tellier worked on "marine ether" and on the "inflammation of radical vinegar".
François-César Le Tellier de Courtanvaux | Contributions to chemistry
The engine's single combustion chamber was regeneratively cooled by the acid oxidiser.
Société d'Etudes pour la Propulsion par Réaction | Auxiliary rocket engines
This continuous slow combustion, which they supposed took place in the lungs, enabled the living animal to maintain its body temperature above that of its surroundings, thus accounting for the puzzling phenomenon of animal heat. Lavoisier continued these respiration experiments in 1789–1790 in cooperation with Armand Seguin. They designed an ambitious set of experiments to study the whole process of body metabolism and respiration using Seguin as a human guinea pig in the experiments. Their work was only partially completed and published because of the disruption of the Revolution; but Lavoisier's pioneering work in this field served to inspire similar research on physiological processes for generations to come.
Antoine Lavoisier | Physiological work
Jean-Robert Petit studied chemistry and physics at the University of Grenoble and received a PhD in 1984 in paleoclimatology on the study of the aeolian dust record from Antarctic ice cores.
Jean-Robert Petit | Introduction
In 1774, Antoine Lavoisier used the reaction of water steam with metallic iron inside an incandescent iron tube to produce hydrogen in his experiments leading to the demonstration of the conservation of mass, which was instrumental in changing chemistry from a qualitative science to a quantitative one.
Iron | Foundations of modern chemistry
François Robert, born in Paris, France the 26th of January, 1951, is a French researcher specializing in isotope geochemistry and cosmochemistry. His work on the isotopes of hydrogen has enhanced the understanding of the origin of water and of organic matter in the solar system. He is famous for his work on lithium, beryllium and boron, light elements formed by the irradiation of interstellar matter. He received a Leonard Medal from the Meteoritical Society in 2011 for his work on the isotopic composition of stable nuclei.
François Robert | Introduction
The isotope was first hypothesized and subsequently imaged by Patrick Blackett in Rutherford's lab 1924: It was a product out of the first man-made transmutation of N and He conducted by Frederick Soddy and Ernest Rutherford in 1917-1919. Its natural abundance in Earth's atmosphere was later detected in 1929 by Giauque and Johnson in absorption spectra.
Oxygen-17 | History
He had an impression that combustion and respiration are chemically identical. Lavoisier demonstrated this with the help of Pierre-Simon Laplace. They both carefully measured the amount of "carbon dioxide and heat given off by a guinea pig as it breathed". Then they contrasted this to "the amount of heat produced when they burned carbon to produce the same amount of carbon dioxide as had been exhaled by the guinea pig". Their conclusion made Lavoisier confident "that respiration is a form of combustion". Also, the result showed that the heat mammals produce through respiration allowed their bodies to be above room temperature.
History of animal testing | History of animal testing
The elements included light; caloric (matter of heat); the principles of oxygen, hydrogen, and azote (nitrogen); carbon; sulfur; phosphorus; the yet unknown "radicals" of muriatic acid (hydrochloric acid), boric acid, and "fluoric" acid; 17 metals; 5 earths (mainly oxides of yet unknown metals such as magnesia, baria, and strontia); three alkalies (potash, soda, and ammonia); and the "radicals" of 19 organic acids. The acids, regarded in the new system as compounds of various elements with oxygen, were given names which indicated the element involved together with the degree of oxygenation of that element, for example sulfuric and sulfurous acids, phosphoric and phosphorous acids, nitric and nitrous acids, the "ic" termination indicating acids with a higher proportion of oxygen than those with the "ous" ending.
Antoine Lavoisier | Chemical nomenclature
Isotopes are specified with a number equal to the integer isotopic mass preceding the atomic symbol. Benzene in which one atom is carbon-14 is written as codice_111 and deuterochloroform is codice_112.
Simplified molecular-input line-entry system | Isotopes
Oliphant took the Frisch–Peierls memorandum to Tizard. As a result, the MAUD Committee was established to investigate further. It directed an intensive research effort. Four universities provided the locations where the experiments were taking place. The University of Birmingham undertook theoretical work, such as determining what size of critical mass was needed for an explosion. This group was run by Peierls, with the help of fellow German refugee scientist Klaus Fuchs. The laboratories at the University of Liverpool and the University of Oxford experimented with different types of isotope separation. Chadwick's group at Liverpool dealt with thermal diffusion, a phenomenon observed in mixtures of mobile particles where the different particle types exhibit different responses to the force of a temperature gradient.
Quebec Agreement | Tube Alloys
She collaborated with Daniel Pfenniger in developing a model to account for a large fraction of the dark baryons, which have not yet been identified under the form of cold molecular gas.
Françoise Combes | Research
His current research focuses on the use of stable isotopes to study earth and environmental science, ecosystems, oil sands, and anthropology.
Fred Longstaffe | Introduction
He won the 1921 Nobel Prize in Chemistry in part for his work on isotopes.
Isotope | Radioactive isotopes
Antoine Lavoisier (1743–1794) was a French chemist. Lavoisier may also refer to:
Lavoisier (disambiguation) | Introduction
Piasecki et al. performed first-principles calculations of the equilibrium distributions of all substituted isotopologues of methane. The overall conclusion of theoretical studies is formula_22 and formula_21vary as decreasing monotonic functions of temperature, and the enrichment of multiply D-substituted > multiply C-D-substituted > multiply C-substituted isotopologues for a same number of substitutions (as shown in this ).
Methane clumped isotopes | Theoretical studies
In his early years, Matignon studied heat of combustion for major gaseous hydrocarbons and standard enthalpy of formation for ethanol, formic acid, acetic acid and various sugars. He extended this work to a family of 70 urea derivatives and formulated several thermochemical rules, for example, that the replacement of hydrogen attached to nitrogen by an alkyl radical increases the heat of combustion more than when the replacement is carried out at a carbon atom. This led to such practical conclusions as nitric esters are more powerful explosives than nitro-derivatives. Those urea studies aimed to understand the processes occurring in living organisms and hinted that formic acid and urea should react at ambient conditions and form formylurea.
Camille Matignon | Research
Sabatier's earliest research concerned the thermochemistry of sulfur and metallic sulfates, the subject for the thesis leading to his doctorate. In Toulouse, he continued his physical and chemical investigations to sulfides, chlorides, chromates and copper compounds. He also studied the oxides of nitrogen and nitrosodisulfonic acid and its salts and carried out fundamental research on partition coefficients and absorption spectra. Sabatier greatly facilitated the industrial use of hydrogenation. In 1897, building on the recent biochemical work of the American chemist, James Boyce, he discovered that the introduction of a trace amount of nickel (as a catalyst) facilitated the addition of hydrogen to molecules of most carbon compounds.
Paul Sabatier (chemist) | Research
The next year, he named this portion oxygen (Greek for acid-former), and the other azote (Greek for no life). Because of his more thorough characterization of it as an element, Lavoisier thus has a claim to the discovery of oxygen along with Priestley and Scheele. He also discovered that the "inflammable air" discovered by Cavendish - which he termed hydrogen (Greek for water-former) - combined with oxygen to produce a dew, as Priestley had reported, which appeared to be water. In "Reflexions sur le Phlogistique" (1783), Lavoisier showed the phlogiston theory of combustion to be inconsistent. Mikhail Lomonosov independently established a tradition of chemistry in Russia in the 18th century; he also rejected the phlogiston theory, and anticipated the kinetic theory of gases.
History of chemistry | Antoine-Laurent de Lavoisier
Isotope masses from: Isotopic compositions and standard atomic masses from: Half-life, spin, and isomer data selected from:
Isotopes of iron | References
By the late 1930s, Schoenheimer’s work had contributed to the rising interest in intermediary metabolism and the isotope method.
Rudolph Schoenheimer | Later work: 1933-1941
The tables below provide cross-sections and excitation energies for fusion reactions producing flerovium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.
Isotopes of flerovium | Yields of isotopes
In 2014, PBS released a three episode documentary series about the search for the basic chemical elements, highlighting seven historical scientists in particular. In episode one of "The Mystery of Matter: Search for the Elements", "Out of Thin Air," Fourcroy's character is played by Yan Tual as he assists Lavoisier in his discovery of oxygen.
Antoine François, comte de Fourcroy | Modern References
Much of this work has been driven by the Earth and planetary science communities, although applications to biological and industrial systems are beginning to emerge.
Isotopes of iron | Introduction
Isotopes are any of the several different forms of an element each having different atomic mass (mass number). Isotope can also refer to:
Isotope (disambiguation) | Introduction
The French scientists moved to Cambridge, where they conducted experiments that conclusively showed that a nuclear chain reaction could be produced in a mixture of uranium oxide and heavy water. In a paper written shortly after they arrived in England, Halban and Kowarski theorised that slow neutrons could be absorbed by uranium-238, forming uranium-239. A letter by Edwin McMillan and Philip Abelson published in the "Physical Review" on 15 June 1940 stated that this decayed to an element with an atomic number of 93, and then to one with an atomic number of 94 and mass of 239, which, while still radioactive, was fairly long-lived.
MAUD Committee | University of Cambridge
The thermonuclear burn would produce (like the fission fuel in the primary) pulsations (generations) of high-energy neutrons with an average temperature of 14 MeV through Jetter's cycle. The cycle is a combination of endothermic and exothermic neutronic reactions involving lithium and deuterium/tritium. The reaction's neutronicity was estimated at ≈0.885 (for a Lawson criterion of ≈1.5). These figures do not count the Li isotope, where the LiD has a neutronicity of ≈0.835 and, along with the cross-sections, were given as group averages from about 2.40 to approximately 2.55 MeV and from 14.0 to 14.1 MeV; the small power group is not statistically present (see also Nuclear fusion).
Castle Bravo | Jetter's cycle
Soddy recognized that emission of an alpha particle followed by two beta particles led to the formation of an element chemically identical to the initial element but with a mass four units lighter and with different radioactive properties. Soddy proposed that several types of atoms (differing in radioactive properties) could occupy the same place in the table. For example, the alpha-decay of uranium-235 forms thorium-231, whereas the beta decay of actinium-230 forms thorium-230. The term "isotope", Greek for "at the same place", was suggested to Soddy by Margaret Todd, a Scottish physician and family friend, during a conversation in which he explained his ideas to her.
Isotope | Radioactive isotopes
He explained the theory of combustion, and challenged the phlogiston theory with his views on caloric. The "Traité" incorporates notions of a "new chemistry" and describes the experiments and reasoning that led to his conclusions. Like Newton's "Principia", which was the high point of the Scientific Revolution, Lavoisier's "Traité" can be seen as the culmination of the Chemical Revolution. Lavoisier's work was not immediately accepted and it took several decades for it gain momentum. This transition was aided by the work of Jöns Jakob Berzelius, who came up with a simplified shorthand to describe chemical compounds based on John Dalton's theory of atomic weights.
Chemical revolution | Antoine Lavoisier
The elements given by Lavoisier are: [[light]], [[caloric theory|caloric]], [[oxygen]], azote ([[nitrogen]]), [[hydrogen]], [[sulphur]], phosphorous ([[phosphorus]]), [[charcoal]], muriatic radical ([[chloride]]), fluoric radical ([[fluoride]]), boracic radical, [[antimony]], [[arsenic]], [[bismuth]], [[cobalt]], [[copper]], [[gold]], [[iron]], [[lead]], [[manganese]], [[mercury (element)|mercury]], molybdena ([[molybdenite]]), [[nickel]], platina ([[platinum]]), [[silver]], [[tin]], ([[tungsten]]), [[zinc]], [[lime (material)|lime]], magnesia ([[magnesium]]), barytes ([[baryte]]), ([[clay]] or earth of [[alum]]), and [[silex]].
Traité Élémentaire de Chimie | Introduction
This technique has been used to quantify the Atlantic Meridional Overturning Circulation (AMOC) during the Last Glacial Maximum (LGM) and during abrupt climate change events in Earth's past, such as Heinrich events and Dansgaard-Oeschger events.
Environmental isotopes | Uranium and related isotopes
Many of these contributions have been linked to experiments, especially to the rich phase diagrams of the high temperature superconductors.
Subir Sachdev | Introduction
Initially, Hahn was not interested, but von Grosse's mention of protactinium changed his mind. "The only question", Hahn later wrote, "seemed to be whether Fermi had found isotopes of transuranian elements, or isotopes of the next-lower element, protactinium. At that time Lise Meitner and I decided to repeat Fermi's experiments in order to find out whether the 13-minute isotope was a protactinium isotope or not. It was a logical decision, having been the discoverers of protactinium." Hahn and Meitner were joined by Fritz Strassmann. Strassmann had received his doctorate in analytical chemistry from the Technical University of Hannover in 1929, and had come to the Kaiser Wilhelm Institute for Chemistry to study under Hahn, believing that this would improve his employment prospects.
Discovery of nuclear fission | Objections
He became part of the Manhattan Project at Columbia University, where he worked on methods to achieve the separation of the uranium-235 from the more plentiful isotope uranium-238 needed to complete an atomic bomb using the enriched uranium. The method of photochemistry that Bigeleisen researched did not lead to an effective method of separating the uranium isotopes, and gaseous diffusion and methods that took advantage of the electromagnetic properties of uranium proved to be more effective means of isotope separation. Bigeleisen's research led to the development of isotope chemistry based on the principle that heavier isotopes formed stronger chemical bonds allowing for the creation of a straightforward theory to explain the progress of chemical reactions through the interaction of isotopes in gaseous form, which he did together with Maria Goeppert-Mayer, who would later win the Nobel Prize in Physics.
Jacob Bigeleisen | Manhattan Project
He then heated the mercuric calc and measured the amount of air released and discovered the quantities were the same. Lavoisier realised that something was absorbed from the air when mercury was heated to make mercuric calc, and that same gas was released when the mercuric calc was heated. Lavoisier concluded that this gas was unrelated to phlogiston, but was in fact a brand new element, which he named oxygen.
Chemistry: A Volatile History | Antoine Lavoisier and the end of phlogiston
Frederick Soddy and Kazimierz Fajans found in 1913 that although these substances emitted different radiation, many of these substances were identical in their chemical characteristics, so shared the same place on the periodic table. They became known as isotopes, from the Greek "" ("same place"). Austrian chemist Friedrich Paneth cited a difference between "real elements" (elements) and "simple substances" (isotopes), also determining that the existence of different isotopes was mostly irrelevant in determining chemical properties. Following British physicist Charles Glover Barkla's discovery of characteristic X-rays emitted from metals in 1906, British physicist Henry Moseley considered a possible correlation between x-ray emissions and physical properties of elements.
History of the periodic table | Radioactivity, isotopes, and the Rutherford model
The name "oxygen" was coined in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and correctly characterized the role it plays in combustion.
Oxygen | Introduction
Lavoisier employed the new nomenclature in his "Traité élémentaire de chimie" ("Elementary Treatise on Chemistry"), published in 1789. This work represents the synthesis of Lavoisier's contribution to chemistry and can be considered the first modern textbook on the subject. The core of the work was the oxygen theory, and the work became a most effective vehicle for the transmission of the new doctrines. It presented a unified view of new theories of chemistry, contained a clear statement of the law of conservation of mass, and denied the existence of phlogiston. This text clarified the concept of an element as a substance that could not be broken down by any known method of chemical analysis and presented Lavoisier's theory of the formation of chemical compounds from elements.
Antoine Lavoisier | "Elementary Treatise of Chemistry"
Cailletet was born in Châtillon-sur-Seine, Côte-d'Or. Educated in Paris, Cailletet returned to Châtillon to manage his father's ironworks. In an effort to determine the cause of accidents that occurred while tempering incompletely forged iron, Cailletet found that heating the iron put it in a highly unstable state, with gases dissolved in it. He then analyzed the gases from blast furnaces, which helped him understand the role of heat in the changes of states (phases) of metals. This brought him to the work of liquefying the various gases. Cailletet succeeded in producing droplets of liquid oxygen in 1877 by a different method than Raoul Pictet: He used the Joule-Thomson effect; oxygen was cooled while highly compressed, then allowed to rapidly expand, cooling it further, resulting in the production of small droplets of liquid oxygen.
Louis Paul Cailletet | Life and work
His early research metallurgical dates from 1838, from a series of very remarkable memoirs succeeded until 1844, while others appeared only in 1851. To determine the composition of the gases successively in blast furnaces, kilns in a puddle in the warming ovens, he was inventing special processes, to draw the gas mixture in warmer regions and most easily accessible, and applied the same methods to study the carbonization of wood in the wheels, to that of the carbonization of coal in coke ovens and review of combustion in the engine locomotives homes alongside Frédéric Sauvage. He was a pioneer in the study of the chemical weathering of silicate minerals and basaltic rocks by carbonic acid.
Jacques-Joseph Ebelmen | Research
In 1923 he formulated Fajans' rules of inorganic chemistry, which are used to predict whether a chemical bond will be covalent or ionic. In the United States he researched nuclear reactions using a cyclotron and discovered a radioactive lead isotope with Voigt, and a new rhenium isotope with Sullivan. He developed the quanticule theory which explained the rule of chemical bondings through electrostatic impacts between quanticules and nuclear cores. He was a member of the Polish Institute of Arts and Sciences in America and of many societies and academies.
Kazimierz Fajans | Scientific work
He is also Associate Editor of Frontiers in Carbon Capture, Storage, and Utilization, which is a section of Frontiers in Energy Research.
Lyesse Laloui | Introduction
Fajans and Otto Hahn were the discoverers of the formula that defined the conditions of the precipitation and absorption of radioactive substances. It is very significant in the context of radiochemical methods of separating and cleaning radioactive substances found in the smallest number. In 1919, Fajans started researching the structure of particle and crystal by the thermochemical and refractometrical methods. The co-relation of Born, Fajans and Haber is one of the basic thermochemical rule. On the basis of his research data Fajans formulated the essential conclusions concerning chemical bonding strength and deformation of ions and particles, such as heat of ion hydration, refraction measurements and the heat of sublimation.
Kazimierz Fajans | Scientific work
During 1773 Lavoisier determined to review thoroughly the literature on air, particularly "fixed air," and to repeat many of the experiments of other workers in the field. He published an account of this review in 1774 in a book entitled "Opuscules physiques et chimiques" (Physical and Chemical Essays). In the course of this review, he made his first full study of the work of Joseph Black, the Scottish chemist who had carried out a series of classic quantitative experiments on the mild and caustic alkalies. Black had shown that the difference between a mild alkali, for example, chalk (CaCO), and the caustic form, for example, quicklime (CaO), lay in the fact that the former contained "fixed air," not common air fixed in the chalk, but a distinct chemical species, now understood to be carbon dioxide (CO), which was a constituent of the atmosphere.
Antoine Lavoisier | Joseph Black's "fixed air"
They subsequently explained why the minor Mo and Mo isotopes of the element molybdenum had become dominant in supernovae stardust explaining an experimental riddle in stardust isotopic abundances.
Donald D. Clayton | Nuclear physics origin of the chemical elements (<a href="Nucleosynthesis">Nucleosynthesis</a>)
The table below provides cross-sections and excitation energies for hot fusion reactions producing moscovium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.
Isotopes of moscovium | Reaction yields
The conversion to simple molecules (i.e. H for hydrogen) is required prior to IRMS measurement for stable isotopes. This is due to several reasons with regard to hydrogen: The classical offline preparation for the conversion is combustion over CuO at > 800 °C in sealed quartz tubes, followed by the isolation of resulting water and the reduction to H over hot metal at 400 ~1000 °C on a vacuum line. The produced gas is then directly injected into the dual-inlet mass spectrometer for measurement. The metals used for the reduction to H includes U, Zn, Cr, Mg and Mn, etc.
Hydrogen isotope biogeochemistry | Offline combustion and reduction
Shrapnel broke Hervy's legs, one of which had to be amputated; he died of infection a few days later. To reduce the danger of explosion, the cast iron was replaced with wrought iron. By 1845, the Belgian chemists Daniel-Joseph-Benoît Mareska (1803-1858) and François-Marie-Louis Donny (1822-1896) had replaced the iron with copper and lead. A description of the apparatus and its operation was provided by the French chemist Charles-Adolphe Wurtz:
Adrien-Jean-Pierre Thilorier | Apparatus for producing liquid carbon dioxide