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

100 g/mol

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

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e