Hardness of water? Please, I need some HELP!!!?
25-ml aliquots of a solution (0.5215- CaCO3 is dissolved in 12M HCL and the resulting solution is diluted to 250 ml.) are titrated with EDTA to the Eriochrome Black T end point. A blank containing a small measured amount of Mg2+ requires 2.60 ml of the EDTA to reach the end point. An aliquot to which the same amount of Mg2+ is added requires 28.55 ml of the EDTA to reach the end point.
1. How many ml of EDTA are needed to titrate the Ca2+ ion in the aliquot?
2. How many moles of EDTA are there in the volume obtainedin part 1?
3. What is the molarity of the EDTA solution?
A 100-ml sample of hard water is titrated with EDTA solutionin problem 1. The same amount of Mg2+ is added as previously and the volume of EDTA required is 22.44 ml
1. What volume of EDTA is used in titrating the Ca2+ in the hard water?
2. How many moles of EDTA are there in that volume?
3. How many moles of Ca2+ are there in the 100ml of water?
4. If the Ca2+ comes from CaCO3 how many moles of CaCO3 are there in one L of the water? How many grams of CaCO3 per L?
5. If 1ppm CaCO3=1mg per L what is the water hardness in ppm CaCO3?