Saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten tablets with total mass of 0.5797 g were dissolved in water. The solution was then oxidized to convert all the sulfur to sulfate ion, which was precipitated by adding an excess of barium chloride solution. The mass of BaSO4 obtained was 0.5179 g. What is the average mass of saccharin per tablet?

Question

DrBob222 · Accepted Answer

moles BaSO4 = grams/molar mass = ??
moles S = moles BaSO4
moles S = moles saccharin (1 S per molecule saccharin).
g saccharin = moles x molar mass
That's for 10 tablets; divide the total mass by 10 to obtain mass/tablet.

Let me pose a separate question. Why go to all that work above. Why not just divide 0.5797 by 10 to obtain the mass of 1 tablet? Answer: That will give you the mass of 1 tablet, true enough, BUT not all of each tablet is pure saccharin. A binder is added to each tablet, too.