Question

Calculate the value for total water hardness (amount of Ca + Mg). This will be reported in terms of CaCO3 in mg/L. The moles of (Ca+Mg) is equal to the moles of EDTA used in the titration. Multiply the molarity of the EDTA by the volume in L of EDTA used to get the moles. Then convert the moles to mass using the molar mass of CaCO3. Finally convert your answer to mg and divide by the total volume in L of hard water used to get the concentration in units of mg/L. You can set up the calculation as follows. Get the volume of EDTA from your titration data, use the average concentration calculated above and the volume of hard water used. Total water hardness = (Ca + Mg) Volume Mol EDTA (L) EDTA 1 mol 100 g CaCO3 CaCO3 1000 mg g 1 L hard water titrated L EDTA 1 mol 1 mol

4. Calculate magnesium hardness (mg/L as CaCO3). Use the equation that follows. magnesium hardness = total hardness(from step 3) – calcium hardness(given value) EDTA CaCO 3

Answer 1

To get the calculation done on hardness of water the concentration of the EDTA or the zince solution that was used as standard is needed if you give me that I will give you the complete answer.

Once you know the concentration of zinc solution (N1) then you can calculate the concentration of EDTA solution as

N2 = (N1 x 10)/[(9.5ml + 13.3ml + 12.2ml)/3]

Using this concentration of EDTA you can calculate the concentration of Ca in your water sample as

(N2 x [14+12+12.2]/3)/volume of water taken.

Now this value gives you the concentration of Ca + Mg

You can get the total hardness in terms of CaCO3 by multiplying it by the mol wt of CaCO3 that is 100.