[Atome]

Hello everyone,

I am having some trouble with the following problems and I'd appreciate any help.

Thanks!

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1. An aqueous solution of a certain salt contains chloride ions. A sample of this solution was made by dissolving 17.59 g of the salt in a 1 L volumetric flask. Then 25.00 mL of the solution was treated with excess silver nitrate. The precipitate, AgCl (s), was filtered and dried. If the mass of the dry precipitate was 47.35 g, what was the mass percent of chloride ions in the solution?

2. Thallium (I) sulfate is found in rat poisons. A 500 mg sample of thallium sulfate is taken and added to potassium iodide, to precipitate thallium (I) iodide. When the precipitate is dried, its mass is 200 mg. What is the mass percent of Tl2SO4 in the rat poison?

My Work:

2. I wrote out the chemical equation:

Tl2SO4 + 2KI --> 2TlI + K2SO4

I know that % (m/m) = Mass of Solute/Mass of Sample.

However, I am unsure of what the mass of the sample is.

[Borek]

I know that % (m/m) = Mass of Solute/Mass of Solution.

Mass of sample, not mass of solution.