Chemistry Life in Daily Life Essay

accession outlying(prenominal)ad has the annotation of being the near reactive of all the atoms, with the highest electronegativity value on the periodic table. Be give of this, it prove extremely difficult to isoformer(a). Davy low gear identified it as an element, and was poisoned go trying unsuccessfully to decompose hydrogen fluoride. Two different pill pushers were withal later poisoned in similar attempts, and one of them died as a result. cut druggist Edmond Fremy (1814-1894) very n archeozoic succeeded in isolating fluorine, and though he failed to do so, he inspired his student Henri Moissan (1852-1907) to continue the project.One of the problems obscure in isolating this super reactive element was the fact that it tends to storm whatever container in which it is placed most metals, for instance, will burst into blaze ups in the presence of fluorine. Like the early(a)s before him, Moissan set about to isolate fluorine from hydrogen fluoride by means of e lectrolysisthe use of an electric current to cause a chemical reactionbut in doing so, he apply a platinum-iridium alloy that resisted attacks by fluorine. In 1906, he received the Nobel sugar for his work, and his technique is still employ today in modified pattern.Properties And Uses Of farad A pale green bobble of low density, fluorine rear end combine with all elements except nigh of the noble gases. Even urine will burn in the presence of this highly reactive bosom. atomic digit 9 is as well highly toxic, and can cause severe ruin on contact, yet it excessively exists in harmless heightens, primarily in the min sequencel cognize as fluorspar, or calcium fluoride. The latter gives off a fluorescent light (fluorescence is the term for a type of light non accompanied by heat), and fluorine was named for the mineral that is one of its principal hosts. germ in the 1600s, hydrofluoric sulphurous was utilise for etching glass, and is still use for that consumption today in the manufacture of products such as light bulbs. The vegetable oil industry uses it as a catalysta substance that speeds along a chemical reactionto increase the octane number in gasoline. Fluorine is also used in a polymer comm save known as Teflon, which provides a non-stick surface for frying pans and other cooking-related products. Just as centiliter saw service in human race War I, fluorine was enlisted in World War II to create a weapon system far to a greater extent terrifying than poison gas the atomic bomb.Scientists working on the Manhattan Project, the United States effort to develop the bombs dropped on Japan in 1945, take large quantities of the uranium-235 isotope. This they obtained in large touch off by diffusion of the compound uranium hexafluoride, which consists of molecules containing one uranium atom and six fluorine anions. fluoridization Of Water Long before World War II, health officials in the United States noticed that communities having h igh concentration of fluoride in their drinking water supply tended to suffer a such(prenominal) lower incidence of tooth decay.In some atomic number 18as the concentration of fluoride in the water supply was high enough that it stain peoples teeth still, at the turn of the centuryan era when alveolar hygiene as we know it today was still in its infancythe prevention of tooth decay was an attractive prospect. Perhaps, officials surmised, it would be possible to represent smaller concentrations of fluoride into community drinking water, with a resulting improvement in boilers suit dental health.After World War II, a number of municipalities or so the United States ndertook the fluoridation of their water supplies, using concentrations as low as 1 ppm. at bottom a few years, fluoridation became a hotly debated topic, with proponents pointing to the probable health benefits and opponents arguing from the standpoint of trim backs not directly refer in science. It was an inva sion of personal liberty, they said, for governments to force citizens to drink water which had been supplemented with a foreign substance. During the 1950s, in fact, fluoridation became associated in some circles with Communism meet another manifestation of a government trying to control its citizens.In later years, ironically, antifluoridation efforts became associated with groups on the political left rather than the right. By then, the program line no longer revolved about the issue of government exponent instead the concern was for the health risks involved in introducing a substance lethal in large doses. Fluoride had meanwhile gained application in toothpastes. Colgate took the lead, introducing stannic fluoride in 1955.Three years later, the comp any launched a memorable publicise campaign with commercials in which a little girl showed her mother a report card from the dentist and announced Look, MaNo cavities Within a few years, virtually all brands of toothpaste used fluoride however, the use of fluoride in drinking water remained controversial. As late as 1993, in fact, the issue of fluoridation remained heated enough to spawn a study by the U. S. National Research Council. The council found some improvement in dental health, but not as large as had been claimed by ahead of time proponents of fluoridation. Furthermore, this improvement could be explained by reference to a number of other factors, including fluoride in toothpastes and a generally heightened aw beness of dental health among the U.S. populace.Chlorofluorocarbons some other controversial application of fluorine is its use, along with chlorine and carbon, in chlorofluorocarbons. As noted above, chlorofluorocarbons stimulate been used in refrigerants and propellants another application is as a blowing agent for polyurethane foam. This continued for several decades, but in the 1980s, environmentalists became concerned over depletion of the ozone layer high in Earths atmosphere. U nlike ordinary oxygen (O 2 ), ozone or O 3 is capable of absorbing ultraviolet radiation from the Sun, which would otherwise be prejudicious to human life.It is believed that CFCs catalyze the conversion of ozone to oxygen, and that this whitethorn explain the ozone hole, which is particularly marked over the Antarctic in September and October. As a result, a number of countries signed an agreement in 1996 to eliminate the manufacture of halocarbons, or substances containing halogens and carbon. Manufacturers in countries that signed this agreement, known as the Montreal Protocol, return developed CFC substitutes, most notably hydrochlorofluorocarbons (HCFCs), CFC-like compounds also containing hydrogen atoms.The ozone-layer question is far from settled, however. Critics designate that in fact the depletion of the ozone layer over Antarctica is a natural occurrence, which whitethorn explain why it only occurs at certain times of year. This may also explain why it happens primari ly in Antarctica, far from any place where humans have been using CFCs. (Ozone depletion is far less material in the Arctic, which is much closer to the population centers of the industrialized world. ) In any case, natural sources, such as volcano eruptions, continue to add halogen compounds to the atmosphere.Introduction Chlorine is a highly poisonous gas, greenish-yellow in color, with a tangy smell that induces choking in humans. Yet, it can combine with other elements to form compounds safe for human consumption. Most notable among these compounds is salt, which has been used as a food preservative since at least 3000 B. C. Salt, of course, occurs in nature. By contrast, the first chlorine compound made by humans was probably hydrochloric acid, created by dissolving hydrogen chloride gas in water.The first scientist to work with hydrochloric acid was Persian physician and alchemist Rhazes (ar-Razi c. 64-c. 935), one of the most outstanding scientific minds of the knightly pe riod. Alchemists, who in some ways were the precursors of true chemists, believed that base metals such as iron could be turned into currency. Of course this is not possible, but alchemists in about 1200 did at least succeed in dissolving gold using a mixture of hydrochloric and nitric acids known as aqua regia. The first modern scientist to work with chlorine was Swedish chemist Carl W. Scheele (1742-1786), who also discovered a number of other elements and compounds, including barium, manganese, oxygen, ammonia, and glycerin.However, Scheele, who set-apart it in 1774, thought process that chlorine was a compound only in 1811 did English chemist Sir Humphry Davy (1778-1829) identify it as an element. Another chemist had suggested the name halogen for the alleged compound, but Davy suggested that it be called chlorine instead, after the Greek word chloros , which indicates a peaked(p) yellow color. Uses Of Chlorine The dangers involved with chlorine have made it an sound substa nce to use against stains, plants, animalsand even human beings.Chlorine gas is highly irritating to the mucous membranes of the nose, mouth, and lungs, and it can be detected in line at a concentration of only 3 parts per one million million million (ppm). The concentrations of chlorine used against troops on both sides in World War I ( undertakening in 1915) was, of course, much higher. Thanks to the use of chlorine gas and other antipersonnel agents, one of the most chilling images to pop from that conflict was of soldiers succumbing to poisonous gas. Yet just as it is harmful to humans, chlorine can be harmful to microbes, thus preserving human life.As early as 1801, it had been used in solutions as a bactericidal in 1831, its use in hospitals made it effective as a weapon against a cholera epidemic that swept across Europe. Another well-known(a) use of chlorine is as a whitewashing agent. Until 1785, when chlorine was first establish to use as a bleach, the only way to g et stains and unwanted colors out of textiles or paper was to expose them to sunlight, not continuously an effective method.By contrast, chlorine, still used as a bleach today, can be highly effectivea good debate not to use regular old-fashioned bleach on anything other than white garment. Since the 1980s, makers of bleaches have developed all-color versions to brighten and take out stains from clothing of other colors. ) Calcium hydrocholoride (CaOCl), both a bleaching powder and a disinfectant used in swimming pools, combines both the disinfectant and bleaching properties of chlorine. This and the others discussed here are just some of many, many compounds formed with the highly reactive element chlorine. Particularly notableand controversialare compounds involving chlorine and carbon. Chlorine And essential CompoundsChlorine bonds well with organic substances, or those containing carbon. In a number of instances, chlorine frames part of an organic polymer such as PVC (poly vinyl chloride), used for devising synthetic pipe. Chlorine polymers are also applied in making synthetic rubber, or neoprene. Due to its resistance to heat, oxidation, and oils, neoprene is used in a number of automobile parts. The bonding of chlorine with substances containing carbon has become increasingly controversial because of concerns over health and the environment, and in some cases chlorine-carbon compounds have been outlawed.Such was the fate of DDT, a pesticide soluble in fats and oils rather than in water. When it was discovered that DDT was carcinogenic, or cancer-causing, in humans and animals, its use in the United States was outlawed. Other, less well-known, chlorine-related insecticides have likewise been banned due to their potential for harm to human life and the environment. Among these are chlorine-containing materials once used for alter cleaning. Also notable is the role of chlorine in chlorofluorocarbons (CFCs), which have been used in refrigerants such a s Freon, and in propellants for aerosol sprays.CFCs tend to go away easily, and concerns over their effect on Earths atmosphere have led to the phasing out of their use.Introduction Bromine is a foul-smelling mahogany-red liquid whose name is derived from a Greek word meaning stink. With a boiling point much lower than that of water137. 84F (58. 8C)it readily transforms into a gas. Like other halogens, its vapors are highly irritating to the eyes and throat. It is found primarily in deposits of brine, a solution of salt and water. Among the most significant brine deposits are in Israels Dead Sea, as well as in atomic number 18 and nautical mile.Credit for the isolation of atomic number 35 is usually given to French chemist Antoine-Jerome Balard (1802-1876), though in fact German chemist Carl Lowig (1803-1890) actually spaced it first, in 1825. However, Balard, who published his results a year later, provided a much more detailed explanation of bromines properties. The first u se of bromine actually predated both men by several millennia. To make their historied purple dyes, the Phoenicians used murex mollusks, which contained bromine. (Like the names of the halogens, the word Phoenicians is derived from Greekin this case, a word meaning red or purple, which referred to their dyes.Today bromine is also used in dyes, and other modern uses include applications in pesticides, disinfectants, medicines, and flame retardants. At one time, a compound containing bromine was widely used by the petroleum industry as an additive for gasoline containing lead. ethene dibromide reacts with the lead released by gasoline to form lead bromide (PbBr 2 ), referred to as a scavenger, because it tends to clean the emissions of lead-containing gasoline. However, leaded gasoline was phased out during the late 1970s and early 1980s as a result, demand for ethene dibromide dropped considerably. Halogen LampsThe name halogen is probably familiar to most people because of the term halogen lamp. apply for automobile headlights, spotlights, and floodlights, the halogen lamp is much more effective than ordinary incandescent light. light heat-producing light was first developed in the 1870s and improved during the early part of the twentieth century with the replacement of carbon by tungsten as the principal material in the filament, the area that is heated. Tungsten proved much more durable than carbon when heated, but it has a number of problems when feature with the gases in an incandescent bulb.As the light bulb continues to burn for a period of time, the tungsten filament begins to thin and will in conclusion break. At the same time, tungsten begins to accumulate on the surface of the bulb, dimming its light. However, by adding bromine and other halogens to the bulbs gas fillingthus making a halogen lampthese problems are alleviated. As tungsten evaporates from the filament, it combines with the halogen to form a vapourised compound that circulates wit hin the bulb. Instead of depositing on the surface of the bulb, the compound remains a gas until it comes into contact with the filament and breaks down.It is then redeposited on the filament, and the halogen gas is free to combine with newly evaporated tungsten. Though a halogen bulb does eventually break down, it lasts much longer than an ordinary incandescent bulb and burns with a much brighter light. Also, because of the decreased tungsten deposits on the surface, it does not begin to dim as it nears the end of its life.Introduction First isolated in 1811 from ashes of seaweed, iodine has a name derived from the Greek word meaning violet-coloreda reference to the fact it forms dark purple crystals.During the 1800s, iodine was obtained commercially from mines in Chile, but during the twentieth century wells of brine in Japan, Oklahoma, and Michigan have proven a better source. Uses And Applications Among the best-known properties of iodine is its brilliance in the human diet. T he thyroid gland produces a growth-regulating hormone that contains iodine, and escape of iodine can cause a goiter, a swelling around the neck. Table salt does not naturally contain iodine however, atomic number 11 chloride sold in stores usually contains about 0. 01% sodium iodide, added by the manufacturer. iodine was once used in the development of photography During the early years of photographic technology, the daguerreotype process used silver plates sensitized with iodine vapors. ace compounds are used today in chemical analysis and in synthesis of organic compounds.Introduction Just as fluorine has the distinction of being the most reactive, astatine is the rarest of all the elements. Long after its organism was predicted, chemists still had no luck finding it in nature, and it was only created in 1940 by bombarding bismuth with alpha particles (positively charged helium nuclei).The newly isolated element was given a Greek name meaning unstable. Indeed, no(prenominal ) of astatines 20 known isotopes is stable, and the longest-lived has a half-life of only 8. 3 hours. This has only added to the difficulties involved in learning about this antic element, and therefore it is difficult to say what applications, if any, astatine may have. The most lustrous area involves the use of astatine to treat a condition known as hyperthyroidism, related to an overly active thyroid gland.