- #1
dumuzi
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I'm trying to show my students that [itex]CaCO_3[/itex] is basic.
[itex]Ca^2^+[/itex] comes from [itex]Ca(OH)_2[/itex], which is a weak base due to it's low solubility. [itex]CO_3^2^-[/itex] comes from the weak acid [itex]HCO_3^-[/itex]. To compare the two we compare:
1) [itex]Ca^2^+ + H_2O --> Ca(OH)_2 + H_3O^+[/itex]
and
2) [itex]CO_3^2^- + H_2O --> HCO_3^- + OH^-[/itex]
We want to compare the K values. It is clear that equation 2 will have a significantly larger K value and the solution will be basic, but where can a person find a K value for something like equation 1?
Are there charts for the Ka of metal ions?
What order of magnitude is it? I imagine Ka for 1 is <<< Kw
[itex]Ca^2^+[/itex] comes from [itex]Ca(OH)_2[/itex], which is a weak base due to it's low solubility. [itex]CO_3^2^-[/itex] comes from the weak acid [itex]HCO_3^-[/itex]. To compare the two we compare:
1) [itex]Ca^2^+ + H_2O --> Ca(OH)_2 + H_3O^+[/itex]
and
2) [itex]CO_3^2^- + H_2O --> HCO_3^- + OH^-[/itex]
We want to compare the K values. It is clear that equation 2 will have a significantly larger K value and the solution will be basic, but where can a person find a K value for something like equation 1?
Are there charts for the Ka of metal ions?
What order of magnitude is it? I imagine Ka for 1 is <<< Kw