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CaSO 4 · 1 / 2 H 2 O + 1 + 1 / 2 H 2 O → CaSO 4 · 2 H 2 O. This reaction is exothermic and is responsible for the ease with which gypsum can be cast into various shapes including sheets (for drywall), sticks (for blackboard chalk), and molds (to immobilize broken bones, or for metal casting). Mixed with polymers, it has been ...
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
When calcium bisulfite is digested as a food additive, different reactions in metabolic pathways can result. One common pathway results in a reaction that will yield 6%-8% sulfur dioxide. This can go to sulfite when absorbed by the lungs, and the sulfite will be converted to sulfate in the liver by an enzyme called sulfite oxidase. Sulfite can ...
The tetrahydrate crystallizes as a solid solution of Ca 3 (SO 3)2(SO 4). 12H 2 O and Ca 3 (SO 3)2(SO 3). 12H 2 O. The mixed sulfite-sulfate represents an intermediate in the oxidation of the sulfite to the sulfate, as is practiced in the production of gypsum. This solid solution consists of [Ca 3 (SO 3) 2 (H 2 O) 12] 2+ cations and either ...
ce 2 (so 3) 3.3h 2 o + o 2 → ce 2 so 3 (so 4) 2 + 3h 2 o Other rare earth sulfite sulfates can be crystallized as hydrates from a water solution. [ 3 ] These sulfite sulfates can be made by at least three methods.
C 6 A S 3 H 32, sometimes with substitution of Fe for Al, and/or CO 2− 3 for SO 2− 4: Calcium trisulfoaluminate hydrate, or ettringite: AFm: C 4 A S H 12, often with substitution of Fe for Al, and/or various other anions such as OH − or CO 2− 3 for SO 2− 4: Calcium monosulfoaluminate C 3 AH 6: 3CaO · Al 2 O 3 · 6 H 2 O: Hydrogarnet
The name anhydrite was given by A. G. Werner in 1804, because of the absence of water of crystallization, as contrasted with the presence of water in gypsum. Some obsolete names for the species are muriacite and karstenite; the former, an earlier name, being given under the impression that the substance was a chloride (muriate).
Gypsum is moderately water-soluble (~2.0–2.5 g/L at 25 °C) [13] and, in contrast to most other salts, it exhibits retrograde solubility, becoming less soluble at higher temperatures. When gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate ( bassanite , often simply called "plaster") and, if heated ...