1) The strength of the eggshell of birds is determined by the calcium carbonate, CaCO₃, content of the eggshell.
The percentage of calcium carbonate in the eggshell can be determined by gravimetric analysis.
0.412 g of clean, dry eggshell was completely dissolved in a minimum volume of dilute hydrochloric acid.

An excess of a basic solution of ammonium oxalate,
(NH₄)2C₂O₄, was then added to form crystals of
calcium oxalate monohydrate, CaC₂O₄.H₂O.
The suspension was filtered and the crystals were then dried to constant mass.
0.523 g of CaC₂O₄.H₂O was collected.
a. Write a balanced equation for the formation of the calcium oxalate monohydrate precipitate.

Solution

b. Determine the percentage, by mass, of calcium carbonate in the eggshell.

Solution