Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt (% w/w)
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To calculate the purity of the calcium chloride dihydrate (% w/w), we need to determine the amount of calcium chloride dihydrate present in the 10.00 mL sample used for titration.
First, let's calculate the concentration of calcium chloride dihydrate in the original solution:
Concentration of calcium chloride dihydrate (M1) = (moles of EDTA) / (volume of EDTA used)
M1 = (0.0125 mol/L EDTA) / (0.0189 L EDTA)
M1 = 0.662 mol/L
Next, we can calculate the number of moles of calcium chloride dihydrate (CaCl2•2H2O) in 10.00 mL of the original solution:
moles of CaCl2•2H2O = M1 * volume used for titration
moles of CaCl2•2H2O = 0.662 mol/L * 0.0100 L
moles of CaCl2•2H2O = 0.00662 mol
Now, we need to determine the mass of calcium chloride dihydrate in the 10.00 mL sample:
mass of CaCl2•2H2O = moles * molar mass
mass of CaCl2•2H2O = 0.00662 mol * (molar mass of CaCl2•2H2O)
The molar mass of CaCl2•2H2O can be calculated as follows:
molar mass of CaCl2•2H2O = (molar mass of Ca) + 2*(molar mass of Cl) + 2*(molar mass of H2O)
molar mass of CaCl2•2H2O = (40.08 g/mol) + 2*(35.45 g/mol) + 2*(18.02 g/mol)
molar mass of CaCl2•2H2O = 147.02 g/mol
Now substituting the values, we get:
mass of CaCl2•2H2O = 0.00662 mol * 147.02 g/mol
Finally, we can calculate the purity of calcium chloride dihydrate (% w/w):
purity (% w/w) = (mass of CaCl2•2H2O / mass of the sample) * 100
purity (% w/w) = (mass of CaCl2•2H2O / 0.7500 g) * 100
By substituting the values, you will get the purity of the calcium chloride dihydrate (% w/w).