K_{sp}, Solubility of MineralsThe solubility product constant is the equilibrium constant for the dissolution of the solid in water.The K_{sp} value for different substances depends on both the chemical composition and the crystalline form. A few examples for common minerals at 25 deg C is below.
Calcium Carbonate and WaterMinerals containing calcium carbonate have different solubilities in water. Two types of carbonate minerals are listed in the table above. An average value for the K_{sp} of calcium carbonate is about 5 x 10^{-9}.There must be net neutrality so the number of positive charges must equal the number of negative charges in solution. In any basic solution of calcium carbonate, the concentration of protons is much less than the concentration of calcium ions and the concentration of bicarbonate anions is greater than either carbonate or hydroxide anions, so: Effect of CaCO_{3} on pHLet's review what we know so far.
Using the equations above, it is possible to calculate the concentration of any of the species in solution. [CO_{2}] = K_{H}/p_{CO2} {[H^{+}]}^{3} = [CO_{2}]^{2}(K_{a1})^{2}(K_{a2})/2(K_{sp}) [HCO_{3}^{-}] = [CO_{2}](K_{a1})/[H^{+}] = 2 (K_{sp})([H^{+}]^{2})/(K_{a1})(K_{a2})[CO_{2}] [CO_{3}^{2-}] = (K_{a1})(K_{a2})[CO_{2}]/[H^{+}]^{2} |