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Electrolysis
In chemistry and manufacturing, electrolysis is a technique that uses Direct current, direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of chemical element, elements from naturally occurring sources such as ores using an electrolytic cell. The voltage that is needed for electrolysis to occur is called the decomposition potential. The word "lysis" means to separate or break, so in terms, electrolysis would mean "breakdown via electricity." Etymology The word "electrolysis" was introduced by Michael Faraday in 1834, using the Greek language, Greek words "amber", which since the 17th century was associated with electrical phenomena, and ' meaning "dissolution". Nevertheless, electrolysis, as a tool to study chemical reactions and obtain pure chemical element, elements, precedes the coinage of the term and formal description by Faraday. History In the early nineteenth century, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hall–Héroult Process
The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite, aluminium's chief ore, through the Bayer process) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell. The process conducted at an industrial scale, happens at 940–980 °C (1700 to 1800°F) and produces aluminium with a purity of 99.5-99.8%. Recycling aluminum, which does not require electrolysis, is thus not treated using this method. The Hall–Héroult process consumes substantial electrical energy, and its electrolysis stage can produce significant amounts of carbon dioxide if the electricity is generated from high-emission sources. Furthermore, the process generates fluorocarbon compounds as byproducts, contributing to both air pollution and climate change. Process Difficulties faced Elemental aluminium cannot be produced by the electrolysis of an aqueous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laws Of Electrolysis
Faraday's laws of electrolysis are quantitative relationships based on the electrochemical research published by Michael Faraday in 1833. First law Michael Faraday reported that the mass () of a substance deposited or liberated at an electrode is directly proportional to the charge (, for which the SI unit is the ampere-second or coulomb). m \propto Q \quad \implies \quad \frac = Z Here, the constant of proportionality, , is called the electro-chemical equivalent (ECE) of the substance. Thus, the ECE can be defined as the mass of the substance deposited or liberated per unit charge. Second law Faraday discovered that when the same amount of electric current is passed through different electrolytes connected in series, the masses of the substances deposited or liberated at the electrodes are directly proportional to their respective chemical equivalent/ equivalent weight (). This turns out to be the molar mass () divided by the valence () : \begin & m \propto E; \quad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrolytic Cell
An electrolytic cell is an electrochemical cell that utilizes an external source of electrical energy to force a chemical reaction that would otherwise not occur. The external energy source is a voltage applied between the cell's two electrodes; an anode (positively charged electrode) and a cathode (negatively charged electrode), which are immersed in an electrolyte solution. This is in contrast to a galvanic cell, which itself is a source of electrical energy and the foundation of a battery. The net reaction taking place in an electrolytic cell is a non-spontaneous reaction (reverse of a spontaneous reaction), i.e., the Gibbs free energy is +ve, while the net reaction taking place in a galvanic cell is a spontaneous reaction, i.e., the Gibbs free energy is - ve. Principles In an electrolytic cell, a current passes through the cell by an external voltage, causing a non-spontaneous chemical reaction to proceed. In a galvanic cell, the progress of a spontaneous chemical reacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Martin Hall
Charles Martin Hall (December 6, 1863 – December 27, 1914) was an American inventor, businessman, and chemist. He is best known for his invention in 1886 of an inexpensive method for producing aluminium, which became the first metal to attain widespread use since the prehistoric discovery of iron. He was one of the founders of Alcoa, along with Alfred E. Hunt; Hunt's partner at the Pittsburgh Testing Laboratory, George Hubbard Clapp; Hunt's chief chemist, W. S. Sample; Howard Lash, head of the Carbon Steel Company; Millard Hunsiker, sales manager for the Carbon Steel Company; and Robert Scott, a mill superintendent for the Carnegie Steel Company. Together they raised $20,000 to launch the Pittsburgh Reduction Company, which was later renamed Aluminum Company of America and then shortened to Alcoa. Biography Early years Charles Martin Hall was born to Herman Bassett Hall and Sophronia H. Brooks on December 6, 1863, in Thompson, Ohio. Charles's father, Herman, graduated f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium
Gallium is a chemical element; it has Chemical symbol, symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875, elemental gallium is a soft, silvery metal at standard temperature and pressure. In its liquid state, it becomes silvery white. If enough force is applied, solid gallium may fracture conchoidal fracture, conchoidally. Since its discovery in 1875, gallium has widely been used to make alloys with low melting points. It is also used in semiconductors, as a dopant in semiconductor substrates. The melting point of gallium, , is used as a temperature reference point. Gallium alloys are used in thermometers as a non-toxic and environmentally friendly alternative to Mercury (element), mercury, and can withstand higher temperatures than mercury. A melting point of , well below the freezing point of water, is claimed for the alloy galinstan (62–95% gallium, 5–22% indium, and 0–16% tin by weight), but that may be t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humphry Davy
Sir Humphry Davy, 1st Baronet (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several Chemical element, elements for the first time: potassium and sodium in 1807 and calcium, strontium, barium, magnesium and boron the following year, as well as for discovering the elemental nature of chlorine and iodine. Davy also studied the forces involved in these separations, inventing the new field of electrochemistry. Davy is also credited with discovering clathrate hydrates. In 1799, he experimented with nitrous oxide and was astonished at how it made him laugh. He nicknamed it "laughing gas" and wrote about its potential as an Anesthesia, anaesthetic to relieve pain during surgery. Davy was a baronet, President of the Royal Society (PRS), Member of the Royal Irish Academy (MRIA), a founder member and Fellow of the Geological Society of London, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luigi Galvani
Luigi Galvani ( , , ; ; 9 September 1737 – 4 December 1798) was an Italian physician, physicist, biologist and philosopher who studied animal electricity. In 1780, using a frog, he discovered that the muscles of dead frogs' legs twitched when struck by an electrical spark. This was an early study of bioelectricity, following experiments by John Walsh (scientist), John Walsh and Hugh Williamson. Early life Luigi Galvani was born to Domenico Galvani and Barbara Caterina Foschi, in Bologna, then part of the Papal States. The house in which he was born may still be seen on Via Marconi, 25, in the center of Bologna. Domenico was a goldsmith. His family had produced several illustrious men. Galvani then began taking an interest in the field of "medical electricity". This field emerged in the middle of the 18th century, following electrical researches and the discovery of the effects of electricity on the human body by scientists including Bertrand Bajon and Ramón María Termey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Héroult
Paul (Louis-Toussaint) Héroult (10 April 1863 – 9 May 1914) was a French scientist. He was one of the inventors of the Hall-Héroult process for smelting aluminium, and developed the first successful commercial electric arc furnace. He lived in Thury-Harcourt, Normandy. Life and career Paul Héroult read Henri Sainte-Claire Deville's treatise on aluminium, when he was 15 years old. At that time, aluminium was as expensive as silver and was used mostly for luxury items and jewellery. Héroult wanted to make it cheaper. He succeeded in doing so when he discovered the electrolytic aluminium process in 1886. The same year, in the United States, Charles Martin Hall (1863–1914) was discovering the same process. Because of this, the process was called the Hall–Heroult process. Héroult's second most important contribution is the first commercially successful electric arc furnace (EAF) for steel in 1900. The Héroult furnace gradually replaced the giant smelters for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anhydrous
A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achieve perfect dryness; anhydrous compounds gradually absorb water from the atmosphere so they must be stored carefully. Solids Many salts and solids can be dried using heat, or under vacuum. Desiccators can also be used to store reagents in dry conditions. Common desiccants include phosphorus pentoxide and silica gel. Chemists may also require dry glassware for sensitive reactions. This can be achieved by drying glassware in an oven, by flame, or under vacuum. Dry solids can be produced by freeze-drying, which is also known as lyophilization. Liquids or solvents In many cases, the presence of water can prevent a reaction from happening, or cause undesirable products to form. To prevent this, anhydrous solvents must be used when perform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferdinand Frederick Henri Moissan
Ferdinand Frédéric Henri Moissan (; 28 September 1852 – 20 February 1907) was a French chemist and pharmacist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds. Among his other contributions, Moissan discovered moissanite and contributed to the development of the electric arc furnace. Moissan was one of the original members of the International Atomic Weights Committee. Biography Early life and education Moissan was born in Paris on 28 September 1852, the son of a minor officer of the Eastern Railway Company, Francis Ferdinand Moissan, and a seamstress, Joséphine Améraldine (née Mitel). In 1864 they moved to Meaux, where he attended the local school. During this time, Moissan became an apprentice clockmaker. However, in 1870, Moissan and his family moved back to Paris due to war against Prussia. Moissan was unable to receive the ''grade universitaire'' necessary to attend university. After spending a year in the army, he en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Académie Des Sciences
The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefront of scientific developments in Europe in the 17th and 18th centuries, and is one of the earliest Academy of Sciences, Academies of Sciences. Currently headed by Patrick Flandrin (President of the academy), it is one of the five Academies of the . __TOC__ History The Academy of Sciences traces its origin to Colbert's plan to create a general academy. He chose a small group of scholars who met on 22 December 1666 in the King's library, near the present-day Bibliothèque nationale de France, Bibliothèque Nationale, and thereafter held twice-weekly working meetings there in the two rooms assigned to the group. The first 30 years of the academy's existence were relatively informal, since no statutes had as yet been laid down for the ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Émile Lecoq De Boisbaudran
Paul may refer to: People * Paul (given name), a given name, including a list of people * Paul (surname), a list of people * Paul the Apostle, an apostle who wrote many of the books of the New Testament * Ray Hildebrand, half of the singing duo Paul & Paula * Paul Stookey, one-third of the folk music trio Peter, Paul and Mary * Billy Paul, stage name of American soul singer Paul Williams (1934–2016) * Vinnie Paul, drummer for American Metal band Pantera * Paul Avril, pseudonym of Édouard-Henri Avril (1849–1928), French painter and commercial artist * Paul, pen name under which Walter Scott wrote ''Paul's letters to his Kinsfolk'' in 1816 * Jean Paul, pen name of Johann Paul Friedrich Richter (1763–1825), German Romantic writer Places * Paul, Cornwall, a village in the civil parish of Penzance, United Kingdom *Paul (civil parish), Cornwall, United Kingdom * Paul, Alabama, United States, an unincorporated community *Paul, Idaho, United States, a city *Paul, Nebraska, United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
