[Wsx594]

You have a 50 g sample of a homogenous mixture of sodium chloride,sodium phosphate, and sodium nitrate. You also have two unlabeled bottles 1 containing barium chloride and the other silver nitrate. You prepare 2 individual 10 g samples and dissolve them in water. You then add the solution from bottle 1 to the sample and filter out the precipitate which weighs 7.343 g. Next you repeat and end up with a precipitate that is 15.10 g. What are the mass percentages of the 50 g mixture? Please answer and show steps to help guide me! THANK YOU SO MUCH

[Arkcon]

Per forum rules you should show your attempts at solving the problem before receiving help.

Please begin by showing us what you know, and begin to solve a least parts of this problem.

[Wsx594]

So far in to the problem I know that the smaller of the two precipitates is the precipitate formed from the combination of Sodium Phosphate and Barium Chloride, other than that all I know is that the other precipitate is formed from a reaction between sodium chloride and silver nitrate and calcium phosphate and silver nitrate which yields the ppt as silver chloride and as silver phosphate. I don't understand what the next step to take would be?

[Borek]

Try to write three equations in three unknowns, describing the mixture and its composition. First equation can be

m_NaCl + m_Na3PO4 + m_NaNO3 = 50 g

The other two you have to build using information about precipitate masses, molar masses and stoichiometry. Once you have three equations - solve, this is a simple algebra.

[Wsx594]

Ok I understand how to write the mixture formula to find its weight but if the precipitate weighs 15.10 and 7.343 would the other equations be Ba3(PO4)2=7.343 g and AgCl + Ag3PO4 ?

[Borek]

Yes - just be careful about 50g vs 10g thing, and don't forget to convert between masses of barium and silver compounds and sodium compounds (which requires some stoichiometry).

[Wsx594]

Ok I think I did what your saying correctly and came out with the numbers of Na3PO4 mass= 5.246 g and NaCl mass= 3.447 g and NaNO3 = 1.307 g did I preform the stoichiometry correctly?

[Borek]

Without delving deeper - 5.246 g of sodium phosphate yields 9.631 g of barium phosphate, which is neither 7.343 g nor 15.10 g - so there is something wrong.