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Whewellite / ˈ h juː ə l aɪ t / is a mineral, hydrated calcium oxalate, formula Ca C 2 O 4 ·H 2 O. [6] Because of its organic content it is thought to have an indirect biological origin; this hypothesis is supported by its presence in coal and sedimentary nodules. However, it has also been found in hydrothermal deposits where a biological ...
Thermogravimetric analysis or thermal gravimetric analysis (TGA) is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes. . This measurement provides information about physical phenomena, such as phase transitions, absorption, adsorption and desorption; as well as chemical phenomena including chemisorptions, thermal decomposition, and ...
The precipitation method is the one used for the determination of the amount of calcium in water. Using this method, an excess of oxalic acid, H 2 C 2 O 4, is added to a measured, known volume of water. By adding a reagent, here ammonium oxalate, the calcium will precipitate as calcium oxalate. The proper reagent, when added to aqueous solution ...
Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula CaC 2 O 4 or Ca(COO) 2. It forms hydrates CaC 2 O 4 · n H 2 O , where n varies from 1 to 3.
This distribution is in contrast to other thallus areas, such as the white zone containing only calcium oxalate dihydrate and the dark red zone with chiodectonic acid, chlorophyll, beta-carotene, and additional calcium oxalate dihydrate in the pink sub-zone. The presence of confluentic acid in specific areas without beta-carotene and ...
A salt with this anion is sometimes called an acid oxalate, monobasic oxalate, or hydrogen oxalate. The equilibrium constant (K a) for loss of the first proton is 5.37 × 10 −2 (pK a = 1.27). The loss of the second proton, which yields the oxalate ion, has an equilibrium constant of 5.25 × 10 −5 (pK a = 4.28).
Calcium nitrate can be used as a part of molten salt mixtures. Typical are binary mixtures of calcium nitrate and potassium nitrate or ternary mixtures including also sodium nitrate . [ 11 ] [ 12 ] [ 13 ] Those molten salts can be used to replace thermo oil in concentrated solar power plants for the heat transfer, but mostly those are used in ...
Weddellite, or calcium oxalate dihydrate, crystallises in a tetragonal system: the classic crystal shape is the eight-face bipyramid. Using bright field microscopy, the weddellite crystals are recognised easily by their shape, reminiscent of a postal envelope. More complex shapes of weddellite are possible; the dumbbell shape is not rare and ...