The average pH of precipitation in rural areas is 6.80. Assuming that the pH
Is controlled by the carbonate system, i.e., no anthropogenic acid gases are present in the atmosphere; calculate the amount of calcium carbonate (mg) dissolved per liter of rainwater. pKa1=6.33, KCO2=3.388e-02
I've seen a couple different solutions to these problems and all of them use other constants and numbers that I have no idea where they got them from. Please explain.© BrainMass Inc. brainmass.com March 21, 2019, 12:01 pm ad1c9bdddf
For this question, you must understand that there are many related reactions going on.
CO2 dissolving into water...
CO2 + H2O --> H2CO3
producing the carbonic acid...
Carbonic acid dissociates into.....
H2CO3 --> HCO3- + H+
bicarbonate....which also dissociates (since carbonic acid is diprotic we see two dissociations)
HCO3- --> CO3^2- + H+
Then we have the solubility of calcium carbonate involved....
CaCO3 --> Ca^2+ + CO3^2-
The only pH dependent component of the solubility of CaCO3 is the carbonate (CO3^2-) ...
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