Calcium carbonate equilibrium pressure must exceed total atmospheric pressure of 101 kPa, which happens at 898 °C. Calcium carbonate is poorly soluble in pure water (47 mg/L at normal atmospheric CO partial pressure as shown below). The equilibrium of its solution is given by the equation (with dissolved calcium carbonate on the right): where the solubility product for [Ca] [CO] is given as anywhere from "K" = 3.7×10 to "K" = 8.7×10 at 25 °C, depending upon the data source. What the equation means is that the product of molar concentration of calcium ions (moles of dissolved Ca per liter of solution)
Calcium hydroxide Calcium hydroxide Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca(OH). It is a colorless crystal or white powder and is obtained when calcium oxide (called "lime" or "quicklime") is mixed, or slaked with water. It has many names including hydrated lime, caustic lime, builders' lime, slack lime, cal, or pickling lime. Calcium hydroxide is used in many applications, including food preparation, where it has been identified as E number E526. Limewater is the common name for a saturated solution of calcium hydroxide. Calcium hydroxide is relatively insoluble in water, with a solubility product