Question

A tablet containing calcium carbonateand fillers with a mass of 1.631g was dissolved in HCl. After the fillers were filtered out, the HCl was neutrilized by adding sodium carbonate. The resulting precipitate was pure calcium carbonate (with fillers removed). The solid calcium carbonate was collected on a watch glass that has a mass of 46.719g when empty. After the calcium carbonate had been allowed to dry, the mass of the watch glass plus product was found to be 47.560g.

1)What is the mass of pure calcium carbonate product collected at the end of the experiment?

2)Calculate the mass % calcium carbonate in the tablet.

3)Calculate the mass % calcium in calcium carbonate. This calculation is theoretical and is independent of the data provided.

4)Calcium the number of grams of calcium that were in the table.(hint: this can be obtained using the answers to question 1 & 3).

Answer 1

1) mass of pure calcium carbonate = (mass of watch glass + mass of product) - (mass of empty watch glass)

= (47.560) - (46.719) = 0.841 gm

2)mass of tablet = 1.631 gm = 100%

then 0.841 gm calcium carbonate = 1000.841/1.631 = 51.56%

mass % calcium carbonate in the tablet = 51.56%

3)molar mass of Calcium carbonate = 100.0869 gm/mol

molar mass of calcium = 40.078 gm/mol

100.0869 gm of Calcium carbonate = 100% then

40.078 gm Calcium = 40.078100/100.0869 = 40.043%

4) molar mass of Calcium carbonate = 100.0869 gm/mol

molar mass of calcium = 40.078 gm/mol then 0.841 gm Calcium carbonate contain 40.078 0.841/100.0869

= 0.33676 gm

grams of calcium = 0.33676 gm