Water is a transparent, tasteless and nearly colorless chemical substance, the main constituent of Earth's streams and oceans, the fluids of most living organisms. It is vital for all known forms of life though it provides no calories or organic nutrients, its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient pressure, it forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of its solid state; when finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is water vapor. Water moves continually through the water cycle of evaporation, condensation and runoff reaching the sea. Water covers 71% of the Earth's surface in seas and oceans. Small portions of water occur as groundwater, in the glaciers and the ice caps of Antarctica and Greenland, in the air as vapor and precipitation.
Water plays an important role in the world economy. 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers and canals. Large quantities of water and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of chemical substances. Water is central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, sport fishing, diving; the word water comes from Old English wæter, from Proto-Germanic *watar, from Proto-Indo-European *wod-or, suffixed form of root *wed-. Cognate, through the Indo-European root, with Greek ύδωρ, Russian вода́, Irish uisce, Albanian ujë; the identification of water as a substance Water is a polar inorganic compound, at room temperature a tasteless and odorless liquid, nearly colorless with a hint of blue.
This simplest hydrogen chalcogenide is by far the most studied chemical compound and is described as the "universal solvent" for its ability to dissolve many substances. This allows it to be the "solvent of life", it is the only common substance to exist as a solid and gas in normal terrestrial conditions. Water is a liquid at the pressures that are most adequate for life. At a standard pressure of 1 atm, water is a liquid between 0 and 100 °C. Increasing the pressure lowers the melting point, about −5 °C at 600 atm and −22 °C at 2100 atm; this effect is relevant, for example, to ice skating, to the buried lakes of Antarctica, to the movement of glaciers. Increasing the pressure has a more dramatic effect on the boiling point, about 374 °C at 220 atm; this effect is important in, among other things, deep-sea hydrothermal vents and geysers, pressure cooking, steam engine design. At the top of Mount Everest, where the atmospheric pressure is about 0.34 atm, water boils at 68 °C. At low pressures, water cannot exist in the liquid state and passes directly from solid to gas by sublimation—a phenomenon exploited in the freeze drying of food.
At high pressures, the liquid and gas states are no longer distinguishable, a state called supercritical steam. Water differs from most liquids in that it becomes less dense as it freezes; the maximum density of water in its liquid form is 1,000 kg/m3. The density of ice is 917 kg/m3. Thus, water expands 9% in volume as it freezes, which accounts for the fact that ice floats on liquid water; the details of the exact chemical nature of liquid water are not well understood. Pure water is described as tasteless and odorless, although humans have specific sensors that can feel the presence of water in their mouths, frogs are known to be able to smell it. However, water from ordinary sources has many dissolved substances, that may give it varying tastes and odors. Humans and other animals have developed senses that enable them to evaluate the potability of water by avoiding water, too salty or putrid; the apparent color of natural bodies of water is determined more by dissolved and suspended solids, or by reflection of the sky, than by water itself.
Light in the visible electromagnetic spectrum can traverse a couple meters of pure water without significant absorption, so that it looks transparent and colorless. Thus aquatic plants and other photosynthetic organisms can live in water up to hundreds of meters deep, because sunlight can reach them. Water vapour is invisible as a gas. Through a thickness of 10 meters or more, the intrinsic color of water is visibly turquoise, as its absorption spectrum has
Orcein archil, lacmus and C. I. Natural Red 28, are names for dyes extracted from several species of lichen known as "orchella weeds", found in various parts of the world. A major source is Roccella tinctoria. Orcinol is extracted from such lichens, it is converted to orcein by ammonia and air. In traditional dye-making methods, urine was used as the ammonia source. If the conversion is carried out in the presence of potassium carbonate, calcium hydroxide, calcium sulfate, the result is litmus, a more complex molecule; the manufacture was described by Cocq in 1812 and in the UK in 1874. Edmund Roberts noted orchilla as a principal export of the Cape Verde islands, superior to the same kind of moss found in Italy or the Canary Islands, that in 1832 was yielding an annual revenue of $200,000. Commercial archil is either a paste, it is red in acidic pH and blue in alkaline pH. The chemical components of orcein were elucidated only in the 1950s by Hans Musso; the structures are shown below. A paper published in 1961, embodying most of Musso's work on components of orcein and litmus, was translated into English and published in 2003 in a special issue of the journal Biotechnic & Histochemistry devoted to the dye.
A single alternative structural formula for orcein incorrect, is given by the National Library of Medicine and Emolecules. Orcein is a reddish-brown dye, orchil is a purple-blue dye. Orcein is used as a stain in microscopy to visualize chromosomes, elastic fibers, Hepatitis B surface antigens, copper-associated proteins. Orcein is not approved as a food dye, with E number E121 before E182 after, its CAS number is 1400-62-0. Its chemical formula is C28H24N2O7, it forms dark brown crystals. It is a mixture of phenoxazone derivates - hydroxyorceins and aminoorceinimines. Cudbear is a dye extracted from orchil lichens, it can be used to dye silk, without the use of mordant. Cudbear was developed by Dr Cuthbert Gordon of Scotland: production began in 1758, it was patented in 1758, British patent 727; the lichen is first boiled in a solution of ammonium carbonate. The mixture is cooled and ammonia is added and the mixture is kept damp for 3–4 weeks; the lichen is dried and ground to powder. The manufacture details were protected, with a ten-feet high wall being built around the manufacturing facility, staff consisting of Highlanders sworn to secrecy.
The lichen consumption soon reached 250 tons per year and import from Norway and Sweden had to be arranged. Cudbear was the first dye to be invented in modern times, one of the few dyes to be credited to a named individual. A similar process was developed in France; the lichen is extracted by urine or ammonia the extract is acidified, the dissolved dye precipitates out and is washed. It is dissolved in ammonia again, the solution is heated in air until it becomes purple it is precipitated out with calcium chloride; the resulting insoluble purple solid is known as French purple, a fast lichen dye, much more stable than other lichen dyes. Litmus test Ethnolichenology Orchil, the poor person's purple
Roccella is a lichenized genus of fungi in the family Roccellaceae. Index Fungorum Roccella tinctoria
Chlorine is a chemical element with 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 intermediate between them. Chlorine is a yellow-green gas at room temperature, it is an reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the Pauling scale, behind only oxygen and fluorine. The most common compound of chlorine, sodium chloride, has been known since ancient times. Around 1630, chlorine gas was first synthesised in a chemical reaction, but not recognised as a fundamentally important substance. Carl Wilhelm Scheele wrote a description of chlorine gas in 1774, supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas might be a pure element, this was confirmed by Sir Humphry Davy in 1810, who named it from Ancient Greek: χλωρός, translit. Khlôros, lit.'pale green' based on its colour.
Because of its great reactivity, all chlorine in the Earth's crust is in the form of ionic chloride compounds, which includes table salt. It is the second-most abundant halogen and twenty-first most abundant chemical element in Earth's crust; these crustal deposits are dwarfed by the huge reserves of chloride in seawater. Elemental chlorine is commercially produced from brine by electrolysis; the high oxidising potential of elemental chlorine led to the development of commercial bleaches and disinfectants, a reagent for many processes in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride, many intermediates for the production of plastics and other end products which do not contain the element; as a common disinfectant, elemental chlorine and chlorine-generating compounds are used more directly in swimming pools to keep them clean and sanitary. Elemental chlorine at high concentrations is dangerous and poisonous for all living organisms, was used in World War I as the first gaseous chemical warfare agent.
In the form of chloride ions, chlorine is necessary to all known species of life. Other types of chlorine compounds are rare in living organisms, artificially produced chlorinated organics range from inert to toxic. In the upper atmosphere, chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion. Small quantities of elemental chlorine are generated by oxidation of chloride to hypochlorite in neutrophils as part of the immune response against bacteria; the most common compound of chlorine, sodium chloride, has been known since ancient times. Its importance in food was well known in classical antiquity and was sometimes used as payment for services for Roman generals and military tribunes. Elemental chlorine was first isolated around 1200 with the discovery of aqua regia and its ability to dissolve gold, since chlorine gas is one of the products of this reaction: it was however not recognised as a new substance. Around 1630, chlorine was recognized as a gas by the Flemish chemist and physician Jan Baptist van Helmont.
The element was first studied in detail in 1774 by Swedish chemist Carl Wilhelm Scheele, he is credited with the discovery. Scheele produced chlorine by reacting MnO2 with HCl: 4 HCl + MnO2 → MnCl2 + 2 H2O + Cl2Scheele observed several of the properties of chlorine: the bleaching effect on litmus, the deadly effect on insects, the yellow-green color, the smell similar to aqua regia, he called it "dephlogisticated muriatic acid air" since it is a gas and it came from hydrochloric acid. He failed to establish chlorine as an element. Common chemical theory at that time held that an acid is a compound that contains oxygen, so a number of chemists, including Claude Berthollet, suggested that Scheele's dephlogisticated muriatic acid air must be a combination of oxygen and the yet undiscovered element, muriaticum. In 1809, Joseph Louis Gay-Lussac and Louis-Jacques Thénard tried to decompose dephlogisticated muriatic acid air by reacting it with charcoal to release the free element muriaticum, they did not succeed and published a report in which they considered the possibility that dephlogisticated muriatic acid air is an element, but were not convinced.
In 1810, Sir Humphry Davy tried the same experiment again, concluded that the substance was an element, not a compound. He announced his results to the Royal Society on 15 November that year. At that time, he named this new element "chlorine", from the Greek word χλωρος, meaning green-yellow; the name "halogen", meaning "salt producer", was used for chlorine in 1811 by Johann Salomo Christoph Schweigger. This term was used as a generic term to describe all the elements in the chlorine family, after a suggestion by Jöns Jakob Berzelius in 1826. In 1823, Michael Faraday liquefied chlorine for the first time, demonstrated that what was known as "solid chlorine" had a structure of chlorine hydrate. Chlorine gas was first used by French chemist Claude Berthollet to bleach textiles in 1785. Modern bleaches resulted from further work by Berthollet, who first produced sodium hypochlorite in 1789 in his laboratory in the town of Javel, by passing chlorine gas through a solution of sodium carbonate; the resulting liqu
Arnaldus de Villa Nova
Arnaldus de Villa Nova was a physician and a religious reformer. He was thought to be an alchemist; the fact that several renown alchemists recognized him as an adept reinforces the thesis that he was an alchemist. He was like most wisemen of his time, an astrologer, he was born in the Crown of Aragon Villanueva de Jiloca or Valencia, he studied medicine and he took some courses of theology. After living at the court of Aragon and teaching for many years in the Montpellier School of Medicine, he went to Paris, where he gained a considerable reputation. In 1311 he was summoned to Avignon by Pope Clement V, but he died on the voyage off the coast of Genoa, he is credited with translating a number of medical texts from Arabic, including works by Ibn Sina, Abu-l-Salt, Galen. Many alchemical writings, including Rosarius Philosophorum, Novum Lumen, or Flos Florum, are ascribed to him, but they are not authentic. Collected editions of them were published at Lyon in 1504 and 1532, at Basel in 1585, at Lyon in 1686.
He is the reputed author of important medical works, such as Speculum medicinae and Regimen sanitatis ad regem Aragonum, but many others, such as Breviarium Practicae, were falsely attributed to him. In addition, he wrote many theological works for the reformation of Christianity in Latin and in Valencian, some of them including apocalyptical prophecies. Arnaldus' place and date of birth are debated: some historians believe he was born in Villeneuve-lès-Maguelone, a village near Montpellier. Regardless, he is known in Catalonia and Balearic Islands by the name "Arnau de Vilanova," and it is certain that he wrote most of his works in Valencian. Whatever the reality, Arnaldus had a great reputation as a doctor and alchemist, he studied medicine in Montpellier until 1260. He wandered France and Italy, as part doctor, part ambassador, he was the personal doctor of the King of Aragon from 1281. At the death of Peter III of Aragon in 1285, he left Barcelona for Montpellier. Influenced by Joachim of Fiore, he claimed that in 1378 the world would end and the Antichrist would come.
He was condemned by the University of Paris in 1299, accused of heresy, imprisoned for his ideas of church reform. He was saved through the intervention of Boniface VIII, whom Arnaldus had cured of a painful illness, he was once again imprisoned in Paris around 1304, under pope Benedict XI. The Sorbonne ordered his philosophical works to be burned, he was the master of the school of medicine between 1291 and 1299. His fame as a doctor was immense: among his patients were three kings, he was the first physician. He became ambassador for king of Aragon and Sicily, he sought refuge from the Inquisition at the court of Frederick III in Sicily, was called to Avignon as doctor for pope Clement V. He is behind the papal bull of 8 September 1309, which required of medical students knowledge of some fifteen Greco-Arabic treatises, including ones by Galen and Avicenna, he died in a shipwreck near Genoa in 1311 while on a diplomatic mission. The inquisitor of Tarragona condemned him, fifteen of his propositions were censured.
A list of writings is given by J. Ferguson in his Bibliotheca Chemica. See U. Chevalier, Repertoire des sources hist. &c. Bio-bibliographie. Brazen Head Latin translations of the 12th century Litmus This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed.. "Arnaldus de Villa Nova". Encyclopædia Britannica. 2. Cambridge University Press. P. 625. J. B. Haureau in the Histoire litteraire de la France, vol. 28. McVaugh, Michael. "Arnald of Villanova". Dictionary of Scientific Biography. 1. New York: Charles Scribner's Sons. Pp. 289–291. ISBN 0-684-10114-9. Who is Arnau de Vilanova, full presentation of Arnau de Vilanova and his works provided by the project Arnau DB at the Universitat Autònoma de Barcelona. Http://www.newadvent.org/cathen/15429c.htm http://www.luc.edu/publications/medieval/vol4/daly.htmlWorks attributed to Arnaldus: Excerpta medica - Mscr. Dresd. C.278. 1500, Online-Ausgabe der Sächsischen Landesbibliothek - Staats- und Universitätsbibliothek Dresden Opus aureum.
Frankfurt a. Mayn 1604, Online-Ausgabe der Sächsischen Landesbibliothek - Staats- und Universitätsbibliothek Dresden Hermetis Trismegisti Phoenicum Aegyptiorum Sed et aliarum Gentium Monarchae Conditoris... sive Tabula Smaragdina. 1657, Online-Ausgabe der Sächsischen Landesbibliothek - Staats- und Universitätsbibliothek Dresden Hermetischer Rosenkrantz, Das ist: Vier schöne, außerlesene Chymische Tractätlein. 1682, Online-Ausgabe der Sächsischen Landesbibliothek - Staats- und Universitätsbibliothek Dresden Lewis E 18 Liber de vinis at OPenn
Spaniards, or the Spanish people, are a Romance ethnic group that are indigenous to Spain. They share a common Spanish culture, history and language. Within Spain, there are a number of nationalisms and regionalisms, reflecting the country's complex history and diverse culture. Although the official language of Spain is known as "Spanish", it is only one of the national languages of Spain, is less ambiguously known as Castilian, a standard language based on the medieval romance speech of the Kingdom of Castile in north and central Spain; the Spanish people's heritage includes the pre-Celts and Celts. There are several spoken regional languages, most notably Basque and Galician. There are many populations outside Spain with ancestors who emigrated from Spain and who share a Hispanic culture; the Roman Republic conquered Iberia during the 2nd and 1st centuries BC. As a result of Roman colonization, the majority of local languages, with the exception of Basque, stem from the Vulgar Latin; the Germanic Vandals and Suebi, with part of the Iranian Alans under King Respendial conquered the peninsula in 409 AD.
In turn, the Visigoths established themselves in Spain. The Iberian Peninsula was conquered and brought under the rule of the Arab Umayyads in 711 and by the Berber North African dynasties the Almohads and the Almoravids in the 11th and 12th centuries. Following the eight century Christian Reconquista against the Moors, the modern Spanish state was formed with the union of the Kingdoms of Castille and Aragon, the conquest of the last Muslim Nasrid Kingdom of Granada and the Canary Islands in the late 15th century. In the early 16th century the Kingdom of Navarre was conquered; as Spain expanded its empire in the Americas, religious minorities in Spain such as Jews and Muslims were either converted or expelled and the Catholic church fiercely persecuted heresy during a period known as the Spanish Inquisition. A small number of Spaniards descend from converted Jewish and North Africans, as a result of the 800 years of Moorish occupation of the Iberian Peninsula. In parallel, a wave of emigration to the Americas began, with over 1.86 million Spaniards emigrating to the Spanish Americas during the colonial period and the population of the Spanish Empire had risen to 16.8 million by the end of the 18th century In the post-colonial period, a further 3.5 million Spanish left for the Americas Argentina, Mexico, Chile, Puerto Rico and Cuba.
Spain is home to one of the largest communities of Romani people. The Government's statistical agency CIS estimated in 2007 that the number of Gitanos present in Spain is around one million; the Spanish Roma, which belong to the Iberian Kale subgroup, are a formerly-nomadic community, which spread across Western Asia, North Africa, Europe, first reaching Spain in the 15th century. The population of Spain is becoming diverse due to recent immigration. From 2000 to 2010, Spain had among the highest per capita immigration rates in the world and the second highest absolute net migration in the World and immigrants now make up about 10% of the population; the prolonged economic crisis between 2008 and 2015 reduced both immigration rates and the total number of foreigners in the country, Spain becoming once more a net emigrant country. The earliest modern humans inhabiting Spain are believed to have been Neolithic peoples who may have arrived in the Iberian Peninsula as early as 35,000–40,000 years ago.
In more recent times the Iberians are believed to have arrived or developed in the region between the 4th millennium BC and the 3rd millennium BC settling along the Mediterranean coast. Celts settled in Spain during the Iron Age; some of those tribes in North-central Spain, which had cultural contact with the Iberians, are called Celtiberians. In addition, a group known as the Tartessians and Turdetanians inhabited southwestern Spain and who are believed to have developed a separate civilization of Phoenician influence; the seafaring Phoenicians and Carthaginians successively founded trading colonies along the Mediterranean coast over a period of several centuries. The Second Punic War between the Carthaginians and Romans was fought in what is now Spain and Portugal; the Roman Republic conquered Iberia during the 2nd and 1st centuries BC transformed most of the region into a series of Latin-speaking provinces. As a result of Roman colonization, the majority of local languages, with the exception of Basque, stem from the Vulgar Latin, spoken in Hispania, which evolved into the modern languages of the Iberian Peninsula, including Castilian, which became the main lingua franca of Spain, is now known in most countries as Spanish.
Hispania emerged as an important part of the Roman Empire and produced notable historical figures such as Trajan, Hadrian and Quintilian. The Germanic Vandals and Suebi, with part of the Iranian Alans under King Respendial, arrived in the peninsula in 409 AD. Part of the Vandals with the remaining Alans, now under Geiseric in personal union removed themselves to North Africa after a few conflicts with another Germanic tribe, the Visigoths, who established in Toulouse supported Roman campaigns against the Vandals and Alans in 415–19 AD and became the dominant power in Iberia for three centuries; the Visigoths were romanized in the eastern Empire and Christians, so their integration withi
Bleach is the generic name for any chemical product, used industrially and domestically to whiten clothes, lighten hair color and remove stains. It refers to a dilute solution of sodium hypochlorite called "liquid bleach". Many bleaches have broad spectrum bactericidal properties, making them useful for disinfecting and sterilizing and are used in swimming pool sanitation to control bacteria and algae and in many places where sterile conditions are required, they are used in many industrial processes, notably in the bleaching of wood pulp. Bleaches have other minor uses like removing mildew, killing weeds, increasing the longevity of cut flowers. Bleaches work by reacting with many colored organic compounds, such as natural pigments, turning them into colorless ones. While most bleaches are oxidizing agents, some are reducing agents. Chlorine, a powerful oxidizer, is the active agent in many household bleaches. Since pure chlorine is a toxic corrosive gas, these products contain hypochlorite which releases chlorine when needed.
"Bleaching powder" means a formulation containing calcium hypochlorite. Oxidizing bleaching agents that do not contain chlorine are based on peroxides such as hydrogen peroxide, sodium percarbonate, sodium perborate; these bleaches are called'non-chlorine bleach,"oxygen bleach' or'color-safe bleach.'Reducing bleaches have niche uses, such as sulfur dioxide used to bleach wool, either as gas or from solutions of sodium dithionite. Bleaches react with many other organic substances besides the intended colored pigments, so they can weaken or damage natural materials like fibers and leather, intentionally applied dyes such as the indigo of denim. For the same reason, ingestion of the products, breathing of the fumes, or contact with skin or eyes can cause health damage; the earliest form of bleaching involved spreading fabrics and cloth out in a bleachfield to be whitened by the action of the sun and water. By the 17th century, there was a significant cloth bleaching industry in Western Europe, using alternating alkaline baths and acid baths.
The whole process lasted up to six months. Chlorine-based bleaches, which shortened that process from months to hours, were invented in Europe in the late 18th century. Swedish chemist Scheele discovered chlorine in 1774, in 1785 French scientist Claude Berthollet recognized that it could be used to bleach fabrics. Berthollet discovered sodium hypochlorite, which became the first commercial bleach, named Eau de Javel after the borough in Paris where it was produced. Scottish chemist and industrialist Charles Tennant proposed in 1798 a solution of calcium hypochlorite as an alternative for Javel water, patented bleaching powder in 1799. Around 1820, French chemist Labarraque discovered the disinfecting and deodorizing ability of hypochlorites, was instrumental in popularizing their use for such purpose, his work improved medical practice, public health, the sanitary conditions in hospitals and all industries dealing with animal products. Louis Jacques Thénard first produced hydrogen peroxide in 1818 by reacting barium peroxide with nitric acid.
Hydrogen peroxide was first used for bleaching in 1882, but did not become commercially important until after 1930. Sodium perborate as a laundry bleach had been used in Europe since the early twentieth century, but did not become popular in North America until the 1980s. Colors of natural organic materials arise from organic pigments, such as beta carotene. Chemical bleaches work in one of two ways: An oxidizing bleach works by breaking the chemical bonds that make up the chromophore; this changes the molecule into a different substance that either does not contain a chromophore, or contains a chromophore that does not absorb visible light. This is the mechanism of bleaches based on chlorine but of oxygen-anions which react through initial nucleophilic attack. A reducing bleach works by converting double bonds in the chromophore into single bonds; this eliminates the ability of the chromophore to absorb visible light. This is the mechanism of bleaches based on sulfur dioxide. Sunlight acts as a bleach through a process leading to similar results: high energy photons of light in the violet or ultraviolet range, can disrupt the bonds in the chromophore, rendering the resulting substance colorless.
Extended exposure leads to massive discoloration reducing the colors to white and very faded blue spectrums. The broad-spectrum effectiveness of most bleaches is due to their general chemical reactivity against organic compounds, rather than the selective inhibitory or toxic actions of antibiotics, they irreversibly denature or destroy many proteins, making them versatile disinfectants. However, hypochlorite bleaches in low concentration were found to attack bacteria by interfering with heat shock proteins on their walls. Most industrial and household bleaches belong to three broad classes: Chlorine-based bleaches, whose active agent is chlorine from the decomposition of some chlorine compound like hypochlorite or chloramine. Peroxide-based bleaches, whose active agent is oxygen always from the decomposition of a peroxide compound like hydrogen peroxide. Sulfur dioxide based bleaches, whose active agent is sulfur dioxide from the decomposition of some oxosulfur anion. Chlorine-based bleaches are found in many household "bleach" products, as well as in specialized products for hospitals, public health, water chlo