If the 50.00mL sample from problem 3 above was titrated with EDTA,what volume of a 0.00420 M EDTA solution would be needed to reach the endpoint? (Your answer should be given in milliliters.) (Problem 3 found that .0000625 moles of calcium carbonate were present in the sample)

Answer 1

EDTA forms 1:1 complexes with metals; therefore, 6.25E-5 mols from the previous problem will be that amount with EDTA.
M = mols/L
0.00420 = 6.25E-5/L. Solve for L and convert to mL if desired.