Question

3. After removing membranes from an eggshell, the shell is dried and its mass is recorded as 5.613 g. The egg is transferred to a 250 mL beaker and dissolved in 25 mL of 6 M HCL. After filtering, the solution containing the dissolved eggshell is diluted to 250 mL in a volumetric flask. A 10.00 mL aliquot is placed in 125 mL flask and buffered to a pH of 10. Titrating with 0.0500 M EDTA requires 41.11 mL to reach the end point. Determine the amount calcium in the eggshell as %w/w CaCO3.

Answer 1

mols EDTA = M x L = ?
mols Ca = same since EDTA complexes 1:1
You titrated only 10 mL aliquot of a 250 mL sample so mols in the original sample is mols from above x 250/10 and that is mols Ca in the initial sample. grams Ca = mols Ca x atomic mass Ca and % in sample is
(gCa/mass sample)*100 = ?

Answer 2

3123

Answer 3

The answer is 98.08%
Thanks me laturrr.