1. Cave Chemistry

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

3. Cave Chemistry CaCO 3 (s)  Ca 2+ (aq) + CO 3 2- (aq) K sp (CaCO 3 ) = 4.8 x 10 -9 Calculate solubility in mg/L: Actual solubility: 80 mg/L Why???

4. Effect of [CO 2 ]. What should happen as [CO 2 ] increases? CaCO 3 (s)  Ca 2+ (aq) + CO 3 2- (aq) CO 2 + H 2 O  H 2 CO 3 H 2 CO 3  HCO 3 - + H + Ka 1 (H 2 CO 3 ) = 4.2 x 10 -7 HCO 3 -  CO 3 2- + H + Ka 2 (HCO 3 - ) = 4.8 x 10 -11

5. CaCO 3 (s)  Ca 2+ (aq) + CO 3 2- (aq) CO 2 + H 2 O  H 2 CO 3 H 2 CO 3  HCO 3 - + H + Ka 1 (H 2 CO 3 ) = 4.2 x 10 -7 HCO 3 -  CO 3 2- + H + Ka 2 (HCO 3 - ) = 4.8 x 10 -11 The Key Reaction is:

6. So: 1. Formation of the big hole

7. So: 2. Making those formations