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Calcium carbonate is a chemical compound with the chemical formula Ca CO 3. It is a common substance found in rocks as the minerals calcite and aragonite , most notably in chalk and limestone , eggshells , gastropod shells , shellfish skeletons and pearls .
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure. Units of solubility are given in grams of substance per 100 millilitres of water (g/(100 mL)), unless shown otherwise. The substances are listed in alphabetical order.
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.
The exact value of the CCD depends on the solubility of calcium carbonate which is determined by temperature, pressure and the chemical composition of the water – in particular the amount of dissolved CO 2 in the water. Calcium carbonate is more soluble at lower temperatures and at higher pressures.
The solubility of a specific solute in a specific solvent is generally expressed as the concentration of a saturated solution of the two. [1] Any of the several ways of expressing concentration of solutions can be used, such as the mass, volume, or amount in moles of the solute for a specific mass, volume, or mole amount of the solvent or of the solution.
A solubility equilibrium exists when a chemical compound in the solid state is in chemical equilibrium with a solution containing the compound. This type of equilibrium is an example of dynamic equilibrium in that some individual molecules migrate between the solid and solution phases such that the rates of dissolution and precipitation are equal to one another.
Limestone forms when calcite or aragonite precipitate out of water containing dissolved calcium, which can take place through both biological and nonbiological processes. [41] The solubility of calcium carbonate (CaCO 3) is controlled largely by the amount of dissolved carbon dioxide (CO 2) in the water. This is summarized in the reaction:
Parts per million (ppm) is usually defined as 1 mg/L CaCO 3 (the definition used below). [20] It is equivalent to mg/L without chemical compound specified, and to American degree. Grain per gallon (gpg) is defined as 1 grain (64.8 mg) of calcium carbonate per U.S. gallon (3.79 litres), or 17.118 ppm.