Tip 1: What kind of household appliance does hafnium use?
Tip 1: What kind of household appliance does hafnium use?
Hafnium is a rare metal with a number of valuable properties. It is used in the nuclear industry, it is based on the production of powerful radio tubes. In everyday life it is extremely difficult to meet hafnium.
Extraction
The richest country in hafnium is Australia. More than 600 tons of this metal are concentrated here. The total reserves of hafnium on the planet are estimated at 1,000 tons. In Russia, too, a lot of hafnium - it is found in minerals such as granite, baddeleyite, loparite, etc.Properties
Externally, hafnium looks like a shiny metal withsilvery outflow. Hafnium is very refractory and has a high ability to capture thermal neutrons. Hafnium is chemically inert enough. On its surface an oxide film is formed, which protects it from the action of aggressive media. The best hafnium is dissolved in strong acids - nitrogen, hydrogen fluoride and royal vodka.Application
In household devices, hafnium is practically notis used. It is very rare to find super-power permanent magnets based on hafnium alloys. But the possibility to hold in the hands of hafnium is owned by owners of computers running on microprocessors of the Intel Penryn series. Such processors, for example, are the Intel Core 2 Duo family. In them, hafnium compounds are used as a dielectric. Hafnium has found wide application in the production of powerful radiolamps, the production of rocket engine nozzles and parts of nuclear reactors. Hafnium oxide has a very high melting point and a good index of refraction - on its basis, special glass grades are made for night vision devices, fiber optic networks and thermal imagers. If to fuse tantalum carbide with hafnium carbide, the most refractory alloy in the world will turn out. The melting point is more than 4200 degrees. Based on hafnium, wear-resistant composite coatings, electrodes for argon welding and reflective coatings for X-ray mirrors are made. Let us dwell on another interesting version of the use of hafnium. The isotope of hafnium called 178m2 contains so much excess energy that when exposed to X-rays it can be blown up in an explosive manner. Thus from one gram of hafnium-178m2 so much energy is allocated, how many is allocated at explosion of 50 kgs of trotyl.Tip 2: How Uranium Is Produced
Russia is one of the main countries-producers and suppliers of uranium throughout the world. Uranium is widely used in nuclear power plants, but few know how to get and receive this element.
Instructions
1
Like other metals, uranium is mined in the bowelsOf the Earth. Somewhere this process is completely automated, and it only remains for workers to press the buttons and monitor the operation of the equipment, but in many places the rocks containing this chemical element are mined manually in mines or quarries, using explosives and then transporting pieces of ore to place of its further processing.
2
After that, the rock is crushed and mixed withwater. This is done so that unnecessary heavy impurities quickly settle to the bottom, and they can be removed. Work continues with lighter secondary uranium minerals.
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In the next stage, using an acidic oralkaline leaching, uranium is transferred to the solution (the reagent is selected depending on the valence of the element). After this, it is possible to isolate directly uranium. For this, ion exchange and extraction methods are used. During the chain of successive oxidation-reduction reactions, the raw material is purified from other cations present in it, which can sometimes behave like uranium, but are in fact harmful impurities. Thanks to the extraction and ion exchange techniques, it is possible to isolate uranium even from ores containing a small amount of this chemical element.
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To purify uranium from barium, hafnium and cadmium, itsis placed in a concentrated solution of nitric acid, after which the formed substance passes a few additional purifications. Then, the uranium is crystallized, slowly calcined and treated with hydrogen. As a result, a compound UO2 is formed.
5
The formed oxide is exposed to dryhydrogen fluoride at elevated temperature. At the last stage, by using magnesium or calcium treatment, ready-to-use metallic uranium is obtained.
Tip 3: By whom and when the chemical elements were discovered
Chemical elements scientists have discovered even before 1500year, then in the Middle Ages, already in New time and continue to open now. This was promoted by the development of science in the Age of Enlightenment, an industrial leap forward in the history of mankind, discoveries in spectroscopy, quantum mechanics and nuclear fusion. So which elements, by whom and when were they fixed and included in the chemical table?
Instructions
1
Scientists have discovered copper in ancient times,silver, gold, lead, tin, iron and carbon, as well as other chemical elements - antimony (before 3 thousand years BC), mercury (up to 1500 BC), zinc (about 1300-1000 years before AD) and sulfur (about the 6th century BC).
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The Middle Ages gave humanity three more discoveries -arsenic (1250, the author is not known), bismuth (1450 and the name of the discoverer is also unknown) and phosphorus, which in 1669 was discovered by the German Hennig Brand.
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The 18th century became more prolific: in 1735 Cobalt was discovered by Swede Brandt; in the 1748th platinum the Spaniard de Mendoza; in 1751 the nickel Swede Kronshtedt; in 1766 m 1772th hydrogen and nitrogen British Cavendish; in 1774 the oxygen of J. Priestley; With the participation of the Swede Scheele, manganese, chlorine, barium, molybdenum and tungsten became known; in 1782 the Austrian von Reichenstein discovered an element of tellurium; in 1789 th uranium and zirconium the German Klaproth; in 1790 the British Crawford and Klaproth discovered strontium; in 1794 yttrium was discovered by Finn Gadolin, in 1795 the titan German Klaprot, and chrome and beryllium Frenchman L. Voklen.
4
More chemical elements became known in19 century: in 1801 Hatchet - niobium; in 1802 Ekeberg - tantalum; in 1803 Wollaston and Berzelius discovered palladium and cerium; in 1804, iridium, osmium and rhodium were discovered by scientists from Great Britain; Briton Davy in 1807 found two at once - sodium and potassium; boron in 1808 - Gay-Lussac, calcium and magnesium in the same year the same Davy; iodine was found in 1811 by Courtois; cadmium - 1817th Stromeyer; selenium - in the same Berzelius; lithium - then the Swede Arfedson; silicon in the 1823st Berzelius; vanadiy - in the 1830th Swede Sefström; the discovery of three elements (lanthanum, erbium and terbium) occurred with the participation of the Swede Mosander; ruthenium in 1844 in Kazan was discovered by Klaus; rubidium and cesium - in 1861 - Bunsen and Kirchhoff; thallium - in 1861 Crookes; indie - in 1863 the Germans Reich and Richter; gallium - in 1875 the Frenchman Lecoq de Boisbadran; ytterbium - in 1878 the Swede Marignac; thulium - in the 1879th Kleve; Samaria - in 1879, Lecoq de Boisbadran; holmium - in the 1879th Kleve; scandium - in 1879 Swede Nilsson; praseodymium and neodymium - in 1885 the Austrian Auer von Welsbach; fluorine - in 1886, Moissan; germany - in 1886 Winkler; Gandolia and dysprosium - in the same year Lecoq de Boisbadran; Argon, helium, neon, xenon and krypton - in 1898 the British Ramsay and Traverse; polonium and radium - in 1898 the Curie couple; radon - in the 1899th British Owens and Reesenford and in the same year the Frenchman Debearn discovered actinium.
5
In the 20th century, scientists from different countries found the followingchemical elements: europium - in the 1901st Demarse; lutetium - in 1907 the Frenchman Urben; protactinium - in 1918 the team of German specialists; hafnium - in 1923 the Danes Koster and Heveshi; rhenium - in 1927 the German Noddak; technetium - in 1937 a team of scientists from the United States and Italy; France - in 1923 the Frenchman Perey; to the efforts of American researchers, mankind is responsible for the fame of astatine, neptunium, plutonium, americium, curium, promethium, berkelia, california, einsteinia, fermium and mendelevia; in the Moscow region of Dubna in the 20th century, Nobel, Lawrence, Rutherford, Dubni, Seaborgius, and Borys were found; in Germany in the 80's found meitneria, Hussia, darstadtium, x-rays and copernicias, and in 1999 and 2000 in the same Dubna found fleurvii and Livermorium.
Tip 4: AA Batteries and Other Power Supplies for Digital Technology
For the supply of most household electronic andelectric devices AA and AAA batteries are used. As a rule, they are coal-zinc, alkaline or lithium batteries.
Coal-zinc rechargeable batteries
Depending on the material from which they aremanufactured, the batteries can have different characteristics. The most common batteries are coal-zinc. They use a graphite rod as the cathode, and a zinc glass as an anode. The electrolyte in the coal-zinc batteries is an acid solution. Such batteries have a small capacity and are widely used in pocket flashlights, players and other household devices.Alkaline batteries
In comparison with coal-zinc batteries,manganese-zinc cells have much greater capacity. In them, the anode is made not from graphite, but from manganese oxide. As an electrolyte in manganese-zinc cells, a solution of alkali is used. In everyday life such batteries are called alkaline.Lithium Batteries
Even greater capacity is possessed by lithiumaccumulators. For comparison, the usual capacity for coal-zinc batteries is 300-600 milliamps per hour, and for lithium batteries - more than 2000 milliamps per hour. In lithium sources of supply, the lithium rod is used as an anode, and as a electrolyte a mixture of organic substances. Lithium batteries can work very long, while they are advantageously different from the rest of the batteries in that they are almost not discharged in an unconnected state. Lithium and alkaline batteries are available in AAA and AA cases. Due to the high capacity of lithium batteries, they can be small in size. In disk accumulators "tablets" lithium anodes are used. Disc lithium batteries are used in wrist watches and provide backup power to the BIOS on computers. Cylindrical lithium batteries are used in digital cameras, video cameras, etc.Tip 5: How to determine the cylinder area
Cylindrical geometric shape is used in the manufacture of automobile engines, other technical and household devices, and not only. To determine area cylinder, you need to find its full surface.
Instructions
1
According to Euclid's definition, a cylinder is formedin space as a result of the rotation of the rectangle. Another mathematician, Cavalieri, gave this figure a more general definition in the form of rotation of the generatrix of a straight line. Rotation occurs along a certain guiding line, which, in the simplest case, is a circle. However, the basis cylinder can be any closed figure.
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Bases are always parallel to each other and equal. Moreover, these properties are possessed by any two cross sections, as well as forming segments. To determine area cylinder, we need to use the formula: S = Sb + 2 • So, where Sb - area of the lateral surface, area grounds.
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If you expand the simplest, circular cylinder along the axis of rotation, you get a rectangle with sides equal to the perimeter of the base and the height cylinder. According to the formula of the area of this two-dimensional figure, it is equal to the product of the length of the base to the height. Consequently, area lateral surface cylinder is the result of multiplying the perimeter of the base by the height: Sb = Po • h.
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The considered rectangle and two circles of the base are called a scan cylinder. This term is used when creating technical drawings. The perimeter of the circle is equal to the double product of its radius by the number π, from which: Sb = 2 • π • R • h.
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It remains to find the area of the grounds cylinder. They are also related to the number π and depend on the radius R: So = π • R².
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Substitute the values in the basic formula: S = 2 • π • R • h + 2 • π • R² = 2 • π • R • (h + R).
7
The generalized cylinder The guide line is a polyline, andthe corresponding cylindrical surface can be represented as a series of rectangles formed by pairs of parallel generatrix lines. The cross-sections in this case are polygons, and area such a cylinder is defined similarly to the area of the total surface of the prism.
