[ashleigh782a]

The concentration of Pb2+ in a water sample is determined gravimetrically by adding Na2SO4 to 500.00 mL of water. The lead is present as Pb(NO3)2. The mass of the precipitate obtained was 0.9875 g.

B) calculate the mass of Pb2+ in the precipitate.

C) calculate the concentration (M) of the Pb2+ ions in the water sample

[Arkcon]

I'd like to welcome you, ashleigh782a:, to the Chemical Forums, but I'd like to ask you to read the  Forum Rules{click}.  You agreed to follow these rules when you signed up.

We want to see your attempt.  What did you try, and what did you get?  Do you know what happens when you mix lead solution with soluble sulfate?  Can you write a balanced chemical reaction?  Can you use a balanced chemical reaction to relate masses of products to masses of reactants?  We won't do everything for you.

[snowgumm]

First you could write and balance an equation for the reaction that occurs and determine the identity of the precipitate from that. From that you can then calculate the amount of lead ions and ultimately the concentration of lead ions in the water sample.

[AWK]

Calculate moles and mass of Pb in 0.9875 g of PbSO₄.