Question

EDTA is a very common ligand, which like oxalate, binds to many metals. However, unlike oxalate, which forms two bonds, EDTA forms 6 bonds to the metal. A 0.2481g sample of marble was dissolved in 100 mL, and a 10.00 mL aliquot of the solution was titrated to an endpoint with 23.56 mL of 0.01052 M EDTA solution. What is the molecular weight of the marble

Answer 1

100 g/mol

Step-by-step explanation:

The equation of the reaction;

Ca^2+(aq) + EDTA(aq) -----> (CaEDTA)^2-(aq)

Let CA = concentration of EDTA

VA = volume of EDTA

NA= number of moles of EDTA

CB= concentration of marble

VB = volume of marble

NB= number of moles of marble

CAVA/CBVB = NA/NB

CAVANB=CBVBNA

CB = CAVANB/VBNA

CB = 0.01052 * 23.56 * 1/10.00 * 1

CB = 0.02479 M

number of moles = concentration * volume

number of moles = 0.02479 M * 100.00/1000L

number of moles = 2.479 * 10^-3 moles

number of moles = mass/molar mass

molar mass = 0.2481g/2.479 * 10^-3 moles

molar mass = 100 g/mol