Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Barelover on December 05, 2010, 06:07:22 AM
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Hi :)
This may seem like an obvious question but can someone please help me. I know that lake whitening it caused by the formation of calcium carbonate, but what combines with calcium to form calcium carbonate??
I think it it possibly HCO3-, or H2CO3???
Thank you.
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Hey,
CO2 dissolves in water to form H2CO3.
H2CO3 is in equilibrium with H+ and HCO3- and this in turn is equilibrium with H+ and CO3²-.
And CO3²- can precipitate with Ca²+ as CaCO3
This happens in neutral to basic (so that the equilibrium goes complete to the right) and cold waters (CO2 dissolves beter in cold water).