To determine calcium(II) by substitution titration, an excess of magnesium complex with EDTA was added to 10.00 ml of the solution to be analyzed . The resulting solution was titrated using EDTA solution with a molar concentration of 0.1000mol/L and a correction factor of 1.020 , expending 10.85 ml of titrant. Calculate : the mass (in grams) of calcium (M=40.078g/mol ). in 100.0 ml of the analyzed solution.

To determine the mass of calcium in the analyzed solution, we can use the concept of substitution titration and the stoichiometry of the reaction between calcium and EDTA.<br /><br />Given information:<br />- Volume of the solution to be analyzed: 10.00 mL<br />- Molar concentration of EDTA solution: 0.1000 mol/L<br />- Correction factor for EDTA solution: 1.020<br />- Volume of EDTA solution used in titration: 10.85 mL<br /><br />Step 1: Calculate the moles of EDTA used in titration.<br />Moles of EDTA = Molar concentration × Volume<br />Moles of EDTA = 0.1000 mol/L × 10.85 mL / 1000 mL/L<br />Moles of EDTA = 0.001085 mol<br /><br />Step 2: Calculate the moles of calcium in the 10.00 mL solution.<br />Since the reaction between calcium and EDTA is a 1:1 stoichiometric reaction, the moles of calcium will be equal to the moles of EDTA used in titration.<br />Moles of calcium = 0.001085 mol<br /><br />Step 3: Calculate the mass of calcium in the 10.00 mL solution.<br />Mass of calcium = Moles of calcium × Molar mass of calcium<br />Mass of calcium = 0.001085 mol × 40.078 g/mol<br />Mass of calcium = 0.0434 g<br /><br />Step 4: Calculate the mass of calcium in 100.0 mL of the analyzed solution.<br />Mass of calcium in 100.0 mL = (Mass of calcium in 10.00 mL) × (100.0 mL / 10.00 mL)<br />Mass of calcium in 100.0 mL = 0.0434 g × 10<br />Mass of calcium in 100.0 mL = 0.434 g<br /><br />Therefore, the mass of calcium in 100.0 mL of the analyzed solution is 0.434 grams.