Calcium phosphate and calcium sulfate are two typical salts which show retrograde solubility. solubility. In this solution there are two sources of the sulfate ion; the Na 2 SO 4 and the CaSO 4. The solubilities, determined in four independent experiments, had a standard deviation of ± 3% (1σ), and agreed closely with the published solubility data (Dutrizac, 2002, Linke and Seidell, 1958).

2 Answers. The SO 4 2-coming from the Na 2 SO 4 is 0.10 M, because Na 2 SO 4 is a completely soluble salt. Solubilities of different calcium salts (Loewenthal & Marais, [5]) Calcium salt Formula Solubility as ppm of CaCO 3 at 0°C Calcium bicarbonate Ca(HCO 3) 1620 Calcium carbonate CaCO 3 15 Calcium chloride CaCl 2 336000 Calcium hydroxide Ca(OH) 2 2390 Calcium sulphate CaSO 4 1290 3 Table 1. You may also remember that barium sulphate is formed as a white precipitate during the test for sulphate ions in solution. Maximum solubility of calcium sulfate dihydrate [CaSO 4.2H 2 O] in soft water (g / kg H 2 O): Uses. It is also used as a coagulant in products like tofu. 1923 Askew H. O., "Solubility and Hydrolysis of Calcium Carbonate", Transactions and Proceedings of the Royal Society of New Zealand, 54, 791-796, 1923. Solubility figures for magnesium sulfate and calcium sulfate also vary depending on whether the salt is hydrated or not, but the variations are less dramatic. The ready formation of a precipitate shows that the barium sulphate must be pretty insoluble. The sulfate ion coming from the CaSO 4 is equal to the calcium ion concentration. Calcium sulphate doped with dysprosium was one of the earliest materials to be suggested for use as an OSL dosimeter (Pradhan and Ayyanger, 1976). Solubility of the carbonates The Nuffield Data Book quotes anyhydrous beryllium sulfate, BeSO 4, as insoluble, whereas the hydrated form, BeSO 4.4H 2 O is soluble, with a solubility of about 39 g of BeSO 4 per 100 g of water at room temperature. The solubility for a specific substances pair (solvent and dissoluted substance) depends on many factors. matthew f. 1 decade ago. It is also produced as a by-product of flue gas desulphurisation, which is the process used at thermal power stations to reduce the amount of acid rain that they cause. Calcium sulfate has a solubility of approximately 2000 mg/L as sulfate. Inversely, if you pull heat from this system, e.g. Take the exothermic dissolution of calcium sulfate in water for example: $$\ce{CaSO4_{(s)} <--> Ca^{2+}_{(aq)} + SO4^{2-}_{(aq)} + heat}$$ In this case, the solubility decreases with increasing temperature because by increasing the temperature you are adding heat to the product side. Favorite Answer . The method chosen, however, was DOSL due to the optically stimulated transfer of charge to shallow metastable traps. CaSO4 <--> Ca2+ + SO4 2-setting up an equilibrium expression gives us [Ca2+][SO4 2-] = ksp. The effects of temperature and pressure with time were investigated while monitoring alkalinity, pH and calcium concentration. Relevance. 1925 … In fact, 1 litre of water will only dissolve about 2 mg of barium sulphate at room temperature. In the form of y-anhydrite (the nearly anhydrous form), it is used as a desiccant.

3. was rapid i.e. Working out the units in the calcium phosphate case. SOLUBLE ANHYDRITE, which is obtained by heating calcium sulfate dihydrate at a temperature below 300°C, has a high affinity for water and is used as a desiccant. 2007-11-23 22:42 Stan J Klimas 643×496× (96098 bytes) The temperature dependence of the solubility of calcium sulfate in pure water. Wells R. C., "The Solubility of Calcite in Water in Contact With the Atmosphere, and Its Variation With Temperature", Journal of the Washington Academy of Sciences, 5, 617-622, 1915. Answer Save. from 0 to 2000mg/L in the first 20minutes; (2) Ca(HCO. Soluble anhydrite absorbs water to form calcium sulfate hemihydrate (Plaster of Paris). Calcium sulphate temperature–solubility relationships. It has long been known* that the solubility of calcium sulphate in water attains a maximum at about 35° C, also that the solubility of this compound is increased by the presence of common salt. was introduced. Gypsum (calcium sulphate dihydrate CaSO 4 2H 2 O) is a mineral that occurs in many areas of the world. Here is the solubility product expression for calcium phosphate again: The units this time will be: (mol dm-3) 3 x (mol dm-3) 2 = (mol dm-3) 5 = mol 5 dm-15.