1. Determine the hardness of a water with 120 mg/l of Ca2+ (PM=40) and 48 mg/l di Mg2+ (PM=24). 2. A water presents a total hardness of 35 °F and an HCO3- ion content of 427 mg/L. Calculate the temporary (H) and permanent (Hp) hardness expressed as mg/L CaCO3.
3. Determine the permanent hardness expressed in french degrees and the concentration of Mg2+ and SO,2 expressed in mg/L, of a water with Htot = 30°F [Ca2+ ]=80 mg/) [HCO31 )=268.4 mg/l [Cl" ]=11 mg/l
4. Three water samples (at pH 7.5) have the same alkalinity, equal to 256.2 mg/l, and a content of Ca2+ and Mg2+ ions equal respectively to: i. Ca2+ = 102 mg/l; Mg2+ = 12 mg/l Ca2+ = 54 mg/l; Mg²+ = 18 mg/l + = Ca2+ = 46 mg/l; Mg2+ = 18 mg/l Calculate temporary and permanent hardness in the three cases