Water from a city well is analyzed and found to contain 25 mg/L of (HCO3)^- and 35 mg/L of (CO3)2^-. Calculate the alkalinity of the water as CaCO3.

To calculate the alkalinity of water as CaCO3, we need to determine the total amount of bicarbonate ions (HCO3^-), carbonate ions (CO3)2^-, and hydroxide ions (OH^-) present in the water.

Let's start by calculating the total alkalinity using the given concentration of bicarbonate ions (HCO3^-) and carbonate ions (CO3)2^-.

Alkalinity (as CaCO3) = (HCO3^- concentration) + 2 * (CO3)2^- concentration

Given that the HCO3^- concentration is 25 mg/L and the (CO3)2^- concentration is 35 mg/L, we can substitute these values into the equation:

Alkalinity (as CaCO3) = 25 mg/L + 2 * 35 mg/L
Alkalinity (as CaCO3) = 25 mg/L + 70 mg/L
Alkalinity (as CaCO3) = 95 mg/L

Therefore, the alkalinity of the water as CaCO3 is 95 mg/L.