A water sample was tested for hardness. To titrate Ca2* and Mg2+, a 25.00-mL sample needed 7.39 ml of 0.00964 M EDTA. Another 25.00-mL aliquot was mixed with sufficient NaOH to precipitate out Mg2* as Mg(OH)216). Titration of the clear supernatant liquid required 4.54 mL of the same standard EDTA solution. FW: CaCO3 = 100.09, Mg = 84.31, Ca = 40.078 %3D (Report answers in 3 SF.) a. Calculate the concentration of CaCO3 (FW=100.09) in the sample in ppm. ppm a. Calculate the concentration of MgCO3 (FW=84.31) in the sample in ppm. ppm

A 1.000 mL aliquot of a solution containing Cu²+ and Ni²+ is treated with 25.00 mL of a 0.03703 M EDTA solution. The solution is then back titrated with 0.02138 M Zn²+ solution at a pH of 5. A volume of 22.13 mL of the Zn²+ solution was needed to reach the xylenol orange end point. A 2.000 mL aliquot of the Cu²+ and Ni²+ solution is fed through an ion-exchange column that retains Ni²+. The Cu²+ that passed through the column is treated with 25.00 mL of 0.03703 M EDTA. This solution required 18.53 mL of 0.02138 M Zn²+ for back titration. The Ni²+ extracted from the column was treated witn 25.00 mL of 0.03703 M EDTA. How many milliliters of 0.02138 M Zn²+ is required for the back titration of the Ni²+ solution? volume: mL

What is the mass of pure dry CaCO3 (MW: 100.0869 g/mol) standard used in the standardization of EDTA solution? Assume that 1.758 M EDTA solution was computed based on the titration of CaCO3 standard. The volume of titrant needed to reach the endpoint was 35.00 mL.   Ca2+ + Y4- →  CaY2-         0.1500 g                       5.630 g     6.158 g                                     0.6158 g

The calcium content of a milk sample was to be determined by EDTA titration. A sample weighing 0.206 g was mixed with an aqueous buffer at pH 11.5. A few drops of EBT indicator were added and the solution required 24.25 mL of 1.538 x 10-2 M EDTA to reach the endpoint. Calculate the weight percent of calcium (FW =40) in the milk.