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Berthollet
Claude Louis Berthollet (, 9 December 1748 – 6 November 1822) was a Savoyard-French chemist who became vice president of the French Senate in 1804. He is known for his scientific contributions to the theory of chemical equilibria via the mechanism of reverse chemical reactions, and for his contribution to modern chemical nomenclature. On a practical basis, Berthollet was the first to demonstrate the bleaching action of chlorine gas, and was first to develop a solution of sodium hypochlorite as a modern bleaching agent. Biography Claude Louis Berthollet was born in Talloires, near Annecy, then part of the Duchy of Savoy, in 1749. He started his studies at Chambéry and then in Turin where he graduated in medicine. Berthollet's great new developments in works regarding chemistry made him, in a short period of time, an active participant of the Academy of Science in 1780. Berthollet, along with Antoine Lavoisier and others, devised a chemical nomenclature, or a system of na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine
Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidizing agent, oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Electronegativity#Pauling electronegativity, Pauling scale, behind only oxygen and fluorine. Chlorine played an important role in the experiments conducted by medieval Alchemy, alchemists, which commonly involved the heating of chloride Salt (chemistry), salts like ammonium chloride (sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and . However, the nature of fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antoine Lavoisier
Antoine-Laurent de Lavoisier ( ; ; 26 August 17438 May 1794), 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 ... every other use of common air". He called the air dephlogisticated air, as he thought it was common air deprived of its phlogiston. Since it was therefore in a state to absorb a much greater quantity of phlogiston given off by burning bodies and respiring animals, the greatly enhanced combustion of substances and the greater ease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Equilibria
In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system. This state results when the forward reaction proceeds at the same rate as the reverse reaction. The reaction rates of the forward and backward reactions are generally not zero, but they are equal. Thus, there are no net changes in the concentrations of the reactants and products. Such a state is known as dynamic equilibrium. It is the subject of study of ''equilibrium chemistry''. Historical introduction The concept of chemical equilibrium was developed in 1803, after Berthollet found that some chemical reactions are reversible. For any reaction mixture to exist at equilibrium, the rates of the forward and backward (reverse) reactions must be equal. In the following chemical equation, arrows point both ways to indicate equilibri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Equilibrium
In a chemical reaction, chemical equilibrium is the state in which both the Reagent, reactants and Product (chemistry), products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the Thermodynamic system, system. This state results when the forward reaction proceeds at the same rate as the Reversible reaction, reverse reaction. The reaction rates of the forward and backward reactions are generally not zero, but they are equal. Thus, there are no net changes in the concentrations of the reactants and products. Such a state is known as dynamic equilibrium. It is the subject of study of ''equilibrium chemistry''. Historical introduction The Concept learning, concept of chemical equilibrium was developed in 1803, after Claude Louis Berthollet, Berthollet found that some chemical reactions are Reversible reaction, reversible. For any reaction mixture to exist at equilibrium, the reaction rate, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reversible Reaction
A reversible reaction is a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously. : \mathit aA + \mathit bB \mathit cC + \mathit dD A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B. This is distinct from a reversible process in thermodynamics. Weak acids and bases undergo reversible reactions. For example, carbonic acid: : H2CO3 (l) + H2O(l) ⇌ HCO3−(aq) + H3O+(aq). The concentrations of reactants and products in an equilibrium mixture are determined by the analytical concentrations of the reagents (A and B or C and D) and the equilibrium constant, ''K''. The magnitude of the equilibrium constant depends on the Gibbs free energy change for the reaction. So, when the free energy change is large (more than about 30 kJ mol−1), the equilibrium constant is large (log K > 3) and the concentrations of the reactants at equilibrium are very small. Such a reaction i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Equilibrium
In a chemical reaction, chemical equilibrium is the state in which both the Reagent, reactants and Product (chemistry), products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the Thermodynamic system, system. This state results when the forward reaction proceeds at the same rate as the Reversible reaction, reverse reaction. The reaction rates of the forward and backward reactions are generally not zero, but they are equal. Thus, there are no net changes in the concentrations of the reactants and products. Such a state is known as dynamic equilibrium. It is the subject of study of ''equilibrium chemistry''. Historical introduction The Concept learning, concept of chemical equilibrium was developed in 1803, after Claude Louis Berthollet, Berthollet found that some chemical reactions are Reversible reaction, reversible. For any reaction mixture to exist at equilibrium, the reaction rate, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annecy
Annecy ( , ; , also ) is the Prefectures in France, prefecture and List of communes in France with over 20,000 inhabitants, largest city of the Haute-Savoie Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region of Southeastern France. It lies on the northern tip of Lake Annecy, south of Geneva, Switzerland. Nicknamed the "Pearl of the French Alps" in Raoul Blanchard's monograph describing its location between lake and mountains, the town controls the northern entrance to the lake gorge. Due to a lack of available building land between the lake and the protected Semnoz mountain, its population has remained stable, around 50,000 inhabitants, since 1950. However, the 2017 merger with several ex-communes extended the population of the city to 128,199 inhabitants and that of the Urban unit, urban area to 177,622, placing Annecy seventh in the Auvergne-Rhône-Alpes region. Switching from the County of Geneva, counts of Geneva's dwelling in the 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Law Of Definite Proportions
In chemistry, the law of definite proportions, sometimes called Proust's law or the law of constant composition, states that a given chemical compound contains its constituent elements in a fixed ratio (by mass) and does not depend on its source or method of preparation. For example, oxygen makes up about 8/9 of the mass of any sample of pure water, while hydrogen makes up the remaining 1/9 of the mass: the mass of two elements in a compound are always in the same ratio. Along with the law of multiple proportions, the law of definite proportions forms the basis of stoichiometry. History The law of definite proportion was given by Joseph Proust in 1797. At the end of the 18th century, when the concept of a chemical compound had not yet been fully developed, the law was novel. In fact, when first proposed, it was a controversial statement and was opposed by other chemists, most notably Proust's fellow Frenchman Claude Louis Berthollet, who argued that the elements could combin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Proust
Joseph Louis Proust (26 September 1754 – 5 July 1826) was a French people, French chemist. He was best known for his discovery of the law of definite proportions in 1797, stating that chemical compounds always combine in constant proportions. Life Joseph-Louis Proust was born on 26 September 1754 in Angers, France. His father served as an apothecary in Angers. Joseph studied chemistry in his father's shop and later went to Paris where he gained the appointment of apothecary in chief to the Pitié-Salpêtrière Hospital, Salpêtrière. He also taught chemistry with Pilâtre de Rozier, a famous aeronaut. Under Carlos IV's influence Proust went to Spain. There he taught at the Chemistry School in Segovia and at the University of Salamanca. But when Napoleon invaded Spain, they burned Proust's laboratory and forced him back to France. On 5 July 1826 he died in Angers, France. The mineral proustite (Ag3AsS3) is named in his honour. Chemistry studies Proust's largest accomplishment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-stoichiometric Compound
Non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); most often, in such materials, some small percentage of atoms are missing or too many atoms are packed into an otherwise perfect lattice work. Contrary to earlier definitions, modern understanding of non-stoichiometric compounds view them as homogeneous, and not mixtures of stoichiometric chemical compounds. Since the solids are overall electrically neutral, the defect is compensated by a change in the charge of other atoms in the solid, either by changing their oxidation state, or by replacing them with atoms of different elements with a different charge. Many metal oxides and sulfides have non-stoichiometric examples; for example, stoichiometric iron(II) oxide, which is rare, has the formula , whereas the more common material is nonstoichiometric, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Affinity
In chemical physics and physical chemistry, chemical affinity is the electronic property by which dissimilar chemical species are capable of forming chemical compounds. Chemical affinity can also refer to the tendency of an atom or compound to combine by chemical reaction with atoms or compounds of unlike composition. History Early theories The idea of ''affinity'' is extremely old. Many attempts have been made at identifying its origins. The majority of such attempts, however, except in a general manner, end in futility since "affinities" lie at the basis of all Magic (paranormal), magic, thereby pre-dating science. Physical chemistry, however, was one of the first branches of science to study and formulate a "theory of affinity". The name ''affinitas'' was first used in the sense of chemical relation by German philosopher Albertus Magnus near the year 1250. Later, those as Robert Boyle, John Mayow, Johann Glauber, Isaac Newton, and Georg Stahl put forward ideas on elective ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Nitride
Silver nitride is an explosive chemical compound with symbol Ag3N. It is a black, metallic-looking solid which is formed when silver oxide or silver nitrate is dissolved in concentrated solutions of ammonia, causing formation of the diammine silver complex which subsequently breaks down to Ag3N. The standard free energy of the compound is about +315 kJ/mol, making it an endothermic compound which decomposes explosively to metallic silver and nitrogen gas. History Silver nitride was formerly referred to as fulminating silver, but this can cause confusion with silver fulminate or silver azide, other compounds which have also been referred to by this name. The fulminate and azide compounds do not form from ammoniacal solutions of Ag2O. Fulminating silver was first prepared in 1788 by the French chemist Claude Louis Berthollet. 70 years earlier, in 1716 Johann Kunckel von Löwenstern had already described the preparation. Properties Silver nitride is poorly soluble in water, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
