Cave Chemistry

What cave formation needs: 1. Make a hole in the ground 2 What cave formation needs: 1. Make a hole in the ground 2. Partially fill it with cool formations

Cave Chemistry CaCO3(s)  Ca2+(aq) + CO32-(aq) Ksp(CaCO3) = 4.8 x 10-9 Calculate solubility in mg/L: Actual solubility: 80 mg/L Why???

Effect of [CO2]. What should happen as [CO2] increases? CaCO3(s)  Ca2+(aq) + CO32-(aq) CO2 + H2O  H2CO3 H2CO3  HCO3- + H+ Ka1(H2CO3) = 4.2 x 10-7 HCO3-  CO32- + H+ Ka2(HCO3-) = 4.8 x 10-11

CaCO3(s)  Ca2+(aq) + CO32-(aq) CO2(g) + H2O(l)  H2CO3(aq) H2CO3(aq)  HCO3-(aq) + H+(aq) Ka1(H2CO3) = 4.2 x 10-7 HCO3-(aq)  CO32-(aq) + H+(aq) Ka2(HCO3-) = 4.8 x 10-11 The Key Reaction is:

So: 1. Formation of the big hole

So: 2. Making those formations