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Sodium thiosulfate

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	Sodium thiosulfate
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	Topics Sodium thiosulfate Topic Home Sodium thiosulfate is a colorless crystalCrystal In chemistry and mineralogy, a crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regular... line compound that is more familiar as the pentahydrate, NaSodium Sodium is a chemical element which has the symbol Na , atomic number 11, atomic mass 22.9898 g/mol, oxidation number +1.... ₂SSulfur Sulfur or sulphur is the chemical element in the periodic table that has the symbol S and atomic number 16.... ₂OOxygen Oxygen is a chemical element with the chemical symbol O and atomic number 8.... ₃•5HHydrogen \|-\| Triple point \|\| 13.8033 K, 7.042 kPa... ₂OFacts About Oxygen Oxygen is a chemical element with the chemical symbol O and atomic number 8.... , an efflorescent, monoclinic crystalline substance also called sodium hyposulfite or “hypo.” The thiosulfateThiosulfate Thiosulfate is the anion S2O32-. Thiosulfates are only stable in neutral or alkaline solutions, but not in acidic solutions,... anion is tetrahedral in shape and is notionally derived by replacing one of the oxygenOxygen Overview Oxygen is a chemical element with the chemical symbol O and atomic number 8.... atoms by a sulfurSulfur Sulfur or sulphur is the chemical element in the periodic table that has the symbol S and atomic number 16.... atom in a sulfateSulfate In inorganic chemistry, a sulfate is a salt of sulfuric acid. ... anion. The S-S distance indicates a single bond, implying that the sulfur bears significant negative charge and the S-O interactions have more double bond character. The first protonation of thiosulfate occurs at sulfur. Industrial production and laboratory synthesis On an industrial scale, sodium thiosulfate is produced chiefly from liquid waste products of sodium sulfideSodium sulfide Sodium sulfide is the name used to refer to the chemical compound Na2S but more commonly its hydrate Na2S.9H2O.... or sulfur dyeDye A dye can generally be described as a colored substance that has an affinity to the to which it is being applied.... manufacture. Small scale synthesis is by boiling an aqueous solution of sodium sulfiteSodium sulfite Summary In chemistry, sodium sulfite is a soluble compound of sodium.... with sulfurSulfur Sulfur or sulphur is the chemical element in the periodic table that has the symbol S and atomic number 16.... . Principal reactions and applications Thiosulfate anion characteristically reacts with diluteFacts About Dilution Dilution may refer to:* Reducing the concentration of a chemical... acidFacts About Acid An acid is traditionally considered any chemical compound that when dissolved in water, gives a solution with a pH of less ... s to produce sulfurSulfur Sulfur or sulphur is the chemical element in the periodic table that has the symbol S and atomic number 16.... , sulfur dioxideSulfur dioxide Sulfur dioxide is the chemical compound with the formula SO2.... and waterWater Water is a tasteless, odorless substance that is essential to all known forms of life and is known as the universal solve... : S₂O₃^2-(aq) + 2H⁺(aq) ? S(s) + SO₂(g) + H₂O(l) This reaction has been employed to generate colloidal sulfur. When the protonation is conducted at low temperatures, H₂S₂O₃ can be obtained. It is a strong acid pK_a = 0.6, 1.7. Iodometry In analytical chemistry, the most important use comes from the fact thiosulfate anion reacts stoichiometrically with iodineIodine Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53.... , reducing it to iodideIodide An iodide ion is an iodine atom with a −1 charge.... as it is oxidized to tetrathionateTetrathionate The tetrathionate anion, S4O62-, is a sulfur oxoanion derived from the compound tetrathionic acid, H2S4O6.... : 2 S₂O₃^2-(aq) + IIodine Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53.... ₂(aq) ? S₄O₆^2-(aq) + 2 I^-(aq) Due to the quantitative nature of this reaction, as well as the fact that Na₂S₂O₃•5H₂O has an excellent shelf-life, it is used as a titrant in iodometryIodometry Iodometry is a method of volumetric chemical analysis, a titration where the appearance or disappearance of elementary iodin... . Na₂S₂O₃•5H₂O is also a component of iodine clock experiments. This particular use can be set up to measure the oxygen content of water through a long series of reactions. It is also used in estimating volumetrically, the concentrations of certain compounds in solution, and in estimating the chlorine content in commercial bleaching powder and water. Photographic processing The terminal sulfur atom in S₂O₃^2- binds to soft metals with high affinityAffinity Affinity may refer to:* Affinity , kinship by marriage... . Thus it dissolves silverSilver Silver is a chemical element with the symbol Ag .... halides, e.g. AgBrSilver bromide Summary Silver bromide, a soft, pale-yellow, insoluble salt well known for its unusual sensitivity to light.... , which is a component of photographic emulsions: 2 S₂O₃^2- + AgBr ? [Ag(S₂O₃)₂]^3- + Br^- In this application to photographic processingPhotographic processing Conventional photographic films and papers need to be chemically processed after they have been exposed in order to produce the de... , discovered by John HerschelJohn Herschel Sir John Frederick William Herschel, 1st Baronet KH was an English mathematician and astronomer.... and used for both filmFilm Summary Film is a term that encompasses motion pictures as individual projects, as well as the field in general.... and paper processing, sodium thiosulfate is known as a photographic fixerPhotographic fixer Photographic fixer is a chemical used in the final step in the photographic processing of film or paper.... . Gold extraction Sodium thiosulfate is one component of an alternative lixiviantLixiviant Lixiviant is a liquid medium used in hydrometallurgy to selectively extract the desired metal from the ore or mineral.... to cyanideCyanide A cyanide is any chemical compound that contains the cyano group -C=N, with the carbon atom triple-bonded to the nitro... for extraction of goldGold Gold is a highly sought-after precious metal that for many centuries has been used as money, a store of value and in jewelry... . It forms a strong complex with gold(I) ions, [Au(S₂O₃)₂]^3-. The advantage of this approach is that thiosulfate is essentially non-toxic and that ore types that are refractoryRefractory Refractory materials retain their strength at high temperatures.... to gold cyanidationGold cyanidation Gold cyanidation is a metallurgical technique for extracting gold from low-grade ore by converting the gold to water soluble... (e.g. carbonaceousCarbonaceous Carbonaceous is the defining attribute of a substance rich in carbon.... or Carlin type ores) can be leached by thiosulfate. Some problems with this alternative process include the high consumption of thiosulfate, and the lack of a suitable recovery technique, since [Au(S₂O₃)₂]^3- does not adsorb to activated carbonActivated carbon Activated carbon, also called activated charcoal or activated coal, is a general term which covers carbon materi... , which is the standard technique used in gold cyanidationGold cyanidation Gold cyanidation is a metallurgical technique for extracting gold from low-grade ore by converting the gold to water soluble... to separate the gold complex from the ore slurry. Other uses Sodium thiosulfate is also used: As a component in hand warmerHand warmer Hand warmers are small packets which are held in the hand and produce heat on demand to warm cold hands.... s and other chemical heating padHeating pad A heating pad is a pad used for warming of parts of the body in order to manage pain.... s that produce heat by exothermic crystallization of a supercooledSupercooling Summary Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid.... solution. In Bleach In pH testing of bleach substances. The universal indicatorUniversal indicator Universal Indicator is a pH indicator that has different colors to indicate the range of the pH of the solution it is in.... and any other liquid pH indicator are destroyed by bleach, rendering them useless for testing the pHPH pH is a measure of the acidity of a solution, in terms of activity of hydrogen ions .... . If one first adds sodium thiosulfate to such solutions, it will neutralize the color-removing effects of bleach and allow one to test the pH of bleach solutions with liquid indicators. The relevant reaction is akin to the iodine reaction: thiosulfate reduces the hypochlorite (active ingredient in bleach) and in so doing becomes oxidized to sulfate. The complete reaction is: 4 NaClO + Na₂S₂O₃ + 2 NaOH ? 4 NaCl + 2 Na₂SO₄ + H₂O To dechlorinate tap water for aquariums or treat effluent from waste water treatments prior to release into rivers. The reduction reaction is analogous to the iodine reduction reaction. Treatment of tap water requires between 0.1 grams and 0.3 grams of pentahydrated (crystalline) sodium thiosulfate per 10 liters of water. To lower chlorine levels in swimming pools and spas following super chlorination. To remove iodine stains, e.g. after the explosion of nitrogen triiodideNitrogen triiodide Nitrogen triiodide, also called nitrogen iodide, is a highly explosive compound of nitrogen and iodine, NI3.... . As an antidote to cyanideFacts About Cyanide A cyanide is any chemical compound that contains the cyano group -C=N, with the carbon atom triple-bonded to the nitro... poisoning. Thiosulfate acts as a sulfur donor for the conversion for cyanide to thiocyanate (which can then be safely excreted in the urine), catalyzed by the enzyme rhodanaseRhodanase Rhodanase is a mitochondrial enzyme which detoxifies cyanide by converting it to thiocyanate .... . In bacteriologicalBacteria Bacteria are a major group of living organisms.... water assessment. In the tanningTanning Tanning is the process of conversion of putrescible skin into non putrescible leather.This is commonly done with the acidic ... of leatherLeather Leather is a material created through the tanning of hides, pelts and skins of animals, primarily cows.... . To demonstrate the concept of reaction rateReaction rate The reaction rate for a reactant or product in a particular reaction is defined as the amount of the chemical that is formed... in chemistry classes. The thiosulfateThiosulfate Thiosulfate is the anion S2O32-. Thiosulfates are only stable in neutral or alkaline solutions, but not in acidic solutions,... ion can decompose into the sulfiteSulfite Overview Sulfites are compounds that contain the sulfite ion SO32−.... ion and a colloidal suspension of sulfur, which is opaque. The equation for this acid-catalysed reaction is as follows: S₂O₃^2-(aq) ? SO₃^2-(aq) + S(s) To demonstrate the concept of supercoolingSupercooling Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid.... in physics classes. Melted sodium thiosulfate is very easy to overcool to room temperature and when crystallization is forced, the sudden temperature jump to 48.3°C can be experienced by touch. As part of patinaPatina Patina is a chemical compound formed on the surface of metal.... recipes for copperCopper Copper is a chemical element in the periodic table that has the symbol Cu and atomic number 29.... alloys. Often used in pharmaceutical preparations as an anionic surfactant to aid in dispersion. Treatment of calciphylaxis in hemodialysis patients with End-Stage Renal Disease