1) A groundwater sample is in equilibrium with CaCO3 and CO2(g). The Ca2+ ion concentration is 124 ppm. Determine the concentration of HCO3- (in mol/L). Note that the CO2 partial pressure is not given. Hint: consider which concentrations in the charge balance you can neglect.

2) For the same groundwater sample as in the previous question, determine the [H+] (in mol/L). The Ca2+ ion concentration is still 124 ppm.