Saturday, February 21, 2015

H 2 SO 4 - production: roasting pyrite sulfur dioxide: 4FeS 2 + 11o 2 8 SO 2 + 2 Fe 2 O 3 SO 2


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Posted by (a): Téra2507
Chalcogen elements Outline of the group - O, S, Se, Te, Po - (Oh, Miss, Remove, thinner too, bra) Features: electron configuration is ns2 NP4 have 6 valence electrons, oxygen and sulfur are non-metals, selenium and tellurium metalloids, polonium is a radioactive metal, the oxygen gas is
Sulfur (S) - Occurrence: Free with nearby volcanoes, produces bearings (Poland) - Mining (borehole is injected into water vapor, sulfur is melted and extruded onto the surface); bound S - in sulphides (FeS2 - pyrite, HgS - vermilion), in the sulfate (CaSO4 thinner 2H2O - gypsum) in natural gas, coal and oil, are among the biogenic elements --bound proteins Properties: thinner creates osmiatomovou molecule S8, among the allotropické elements - forms different crystal modifications: at ordinary temperature, sulfur is rhombic (Sα) - žlutá- cooling the vapor formed thinner flowers of sulfur, cooling the liquid sulfur formed plastic (amorphous) sulfur oxidation number: -II, 0, II, III, IV, V, VI Chemical properties: merges directly almost all elements thinner of Cu and Ag reacts even at normal temperature, is a moderately reactive substance has oxidizing and reducing properties: oxidation: S + H 2 H 2 S (t) reductive : S + O 2 SO 2 Use: production of H 2 SO 4, carbon disulfide, sulfides and sulfites, in medicine - on sulfur ointment (in dermatology), vulcanization (curing) rubber winery (to spread barrels) in production gunpowder, matches, dyes, insecticides Sulphur - compounds
A) non-oxygen compounds - H 2 S - hydrogen sulfide, hydrogen sulfide - a colorless, extremely poisonous gas, its odor resembles rotten eggs, flammable, released during decomposition of materials preparation: H 2 + H 2 S S (t) in air burns with a blue flame 2H 2 S + 3O 2 2H 2 O + 2 SO 2 - complete combustion has strong reducing effects of H 2 S + 2HBr Br 2 + S from the H 2 S to form two series of salts: sulfide (S 2-), hydrogen sulphide thinner (HS -) B) OXYGEN COMPOUNDS - Oxides - SO 2 - colorless, poisonous gas acrid odor produced by burning sulfur in the coal and oil in the air reacts with water, produced acid rain (harmful conifers, destroying the facade): SO 2 + H 2 O H 2 SO 3 laboratory preparation thinner and burning sulfur: S + O 2 SO 2 Industrial production: thinner roasting pyrite: 4FeS 2 + 11o 2 2 Fe 2 O 3 + 8 SO 2 in the textile thinner and paper industry - to whiten, food (dried fruit, - as a preservative), production of H 2 SO 4 SO 3 - reacts thinner with water to produce H 2 SO 4 SO 3 + H 2 O H 2 SO 4 preparation: thinner 2 SO 2 + O 2 2 SO 3 (catalyst V 2 O 5)
H 2 SO 4: strong dibasic acid stable, colorless, oily liquid, concentrated: 96 to 98%, it has a dehydrating effect (strongly hygroscopic), does not react with Pb, Au, Pt, diluted: loses oxidizing properties, reacts with non-precious metals: has oxidising characteristics: Cu + 2H 2 SO 4 (conc.) CuSO 4 + SO 2 + 2H 2 O reacts with oxides, hydroxides, salts: MgO + H 2 SO 4 MgSO 4 + H 2 O Ca (OH) 2 + H 2 SO 4 CaSO 4 + 2H 2 O 2NaNO 3 + H 2 SO 4 Na 2 SO 4 + 2HNO 3
H 2 SO 4 - production: roasting pyrite sulfur dioxide: 4FeS 2 + 11o 2 8 SO 2 + 2 Fe 2 O 3 SO 2 is oxidized thinner by oxygen (catalyst V 2 O 5) 2 SO 2 + O 2 2 SO 3 SO 3 absorbs in H 2 SO 4, which was concentrated to 98% - so called. Oleum: SO 3 + H 2 SO 4 H 2 S 2 O 7 + H 2 O 2H 2 SO 4 Using the chemical industry, for the preparation of other compounds, dyes, fertilizers, plastics, cellulose, explosives, performance batteries, refining of mineral oil Sulphate some sulfates thinner contain water of crystallization - the so-called vitriol: CuSO 4 5H 2 O - bluestone, FeSO 4 7H 2 O - green vitriol, ZnSO 4 7H 2 O - white copperas most forms double thinner salts of sulfates - alum: e.g. KCR (SO 4) 2 12H 2 O (dodecahydrate draselnochromitého sulphate) Thiosulphate - Na 2 S 2 O 3 - sodium thiosulfate fixer in analytics (iodometry ) persulfate - Na 2 S 2 O 8 - sodium peroxodisulfate
Selenium (Se) - Characteristics: rare metalloid occurs in six crystalline forms, gray or dark red color insoluble in water, stable, relatively easily combines with oxygen and halogens Oxidation-II, II, IV, VI. - Toxic Occurrence: usually accompanies sulfur and tellurium in the ores Usage: manufacture thinner photocells (photoelectric effect upon irradiation with light directly generate electricity), solar panels copper selenide, gallium and indium in this regard are very promising semiconductor Selenium acts as an antioxidant in the body, which eliminates free radicals and reduces the risk of

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