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How many grams of silver chloride can be prepared by the reaction of 129.8 mL of 0.21 M silver nitrate with 129.8 mL of 0.15 M calcium chloride?
 (answer in grams)
Calculate the concentrations of each ion remaining in solution after precipitation is complete.
Ag+
 
NO3-
 
Ca2+
 
Cl - 

The first thing I did was figured the forumula of the reaction.
2Ag(NO3)+1Ca(Cl2) -> 2AgCl + 1Ca(NO3)2

 that this is a reaction so i got the mols of the reactants from the molarity
.0273 mol Ag(NO3) and .019 mol CaCl2
and then did the correct calculations to find the limiting reactant and
and got the grams silver chloride to be 3.9 (which is correct).
since all the silver was used the concentration of that was zero.

Now I don't know how to get the remaining concentrations. I tried subtracting the limiting reactant  (.0273 molAgCl) from the larger reactant (.038(via ration) CaCl2) to get .0107 mol Cl2, then split in half for .00535 mol Cl, and then divided by total L of concentration (.2596) to get .0206 Molar Cl, but this was wrong. Anyone know what I'm going wrong?

I have a second problem,
 

Saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten tablets with total mass of 0.5726 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 0.5121 g. What is the average mass of saccharin per tablet?
 mg
What is the average mass pecent of saccharin in the tablets?
%

I have no idea what they are asking, so if anyone can give a hint of what direction i should start to solve it in, or rather somehow simplify the problem so i can see what rules to apply in, it would be greatly apprecicated.

[Padfoot]

The first thing I did was figured the forumula of the reaction.
2Ag(NO3)+1Ca(Cl2) -> 2AgCl + 1Ca(NO3)2

 that this is a reaction so i got the mols of the reactants from the molarity
.0273 mol Ag(NO3) and .019 mol CaCl2
and then did the correct calculations to find the limiting reactant and
and got the grams silver chloride to be 3.9 (which is correct).
since all the silver was used the concentration of that was zero.

Good work so far.  In these types of problems it is important to note the states of reactants and products though.  Silver chloride is the precipitate and this is why the concentration of the silver ion is 0.

Using your reaction eqn, you know 0.0273 mol of AgCl reacts with (0.0273/2) mol of CaCl2.  Using simple stoichiometry you can calculate amounts of products.  For the concentrations of ions, take into account the (aq) ions in products and also the ions from unreacted reactants.
For the Chloride ion concentration, note that the amount you have in your AgCl is the amount that has been removed from solution.

I have a second problem,
 

Saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten tablets with total mass of 0.5726 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 0.5121 g. What is the average mass of saccharin per tablet?
 mg
What is the average mass pecent of saccharin in the tablets?
%

Solve the problem in steps. 
0.5121g BaS04 is how many moles?
How many moles of SO4^2-?
How much Sulfur was there?
This is the amount in 10 tablets so how much in 1?
How many moles of saccharin was there (use formula of saccharin)?
Which has a mass of...
Edit:  Compare this to mass of tablet

[scrum]

thanks man