CARBONATE EQUILIBRIA

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Soil Chemistry5-1Section 5- CARBONATE Chemistry CARBONATE EQUILIBRIACarbonates are arguably the most important dissolved component of soil solutions and in alkaline soilsthis statement is even less disputable. Implicit in this statement is the relationship among dissolved carbonatespecies whether or not they are in equilibrium with solid phase metal carbonates . The simplest example ofcarbonates is the control which dissolved carbon dioxide has on water pH and buffering. In this section of thecourse we will consider the effect of carbon dioxide on water pH, the influence of solid phase calcium carbonateon solution composition and the implications of these systems including carbon dioxide, solution and solid phase carbonates can be envisioned.

Calcium carbonate in water with a fixed partial pressure of carbon dioxide. For the case of a fixed partial pressure of carbon dioxide and calcium carbonate dissolved in the aqueous phase one more equation is need to describe the system. This is the solubility product of calcium carbonate: = K ( CaCO ) ( Ca ) ( CO ) o CaCO 3 2 - 3 2 + 3 (19)

  Calcium, Carbonates, Calcium carbonate, And calcium carbonate