What is the percent yield(%)?

Question

For the reaction BaCl2 (aq) + ZnSO4 (aq), BaSO4 precipitates out.

Calculate the percent yield(%) if 15.956 g of BaSO4 precipitates when 1.750 L of 0.0600 M BaCl2 (aq) and 1.460 L of 0.0553 M ZnSO4 (aq) are mixed.

Answer 1

1) Balance the reaction equation:
BaCl2 + ZnSO4 -> BaSO4 + ZnCl2

2) Calculate the amounts we start with
BaCl2 : 1.75 L * 0.0600 mol/L = 0.1050 mol
ZnSO4 : 1.46 L * 0.0553 mol/L = 0.0807 mol
The reaction is limited by the amount of ZnSO4.

3) Calculate the amount of BaSO4 that can be produced maximally
0.0807 mol of BaCl2 will react with 0.0807 mol of ZnSO4 to produce 0.0807 mol of BaSO4. This is 0.0807 * (137.327 + 32.066 +4 * 16.000) =18.835 gram

4) Calculate the yield.
The yield is then 15.956/18.835 = 84.72%

Answer 2

1. Balance the equation.
2. Find the limiting reagent (the compound that will run out first- you get this by comparing how many moles of each compound you have to the moles necessary to comlete the reaction)
-- here you would multiply 1.750L* 0.0600M to get 0.105moles of BaCl2 and multiply 1.460L*0.0553M =0.080738moles of ZnSO4.
------So if this is a 1:1 reaction (already balanced) then the ZnSO4 is the limiting reagent. Therefore 0.08moles of barium chloride added to 0.08moles of zinc sulfate results in 0.08 moles of Barium sulfate-- Theoretically! The remaining BaCl2 remains unreacted. 0.080738 is your theoretical yield.
3. Now we figure out how much BaSO4 we actually got in the experiment- the actual yield. Divide the grams of BaSO4 by its molecular weight =15.956/(mw Ba +mw S + 4*(mw O) = 15.956 / 233.4 = 0.0686 moles
4. Use the percent yield equation--> %yield=actual yield/theoretical yield *100%
-------- 0.0686/0.0807= ~85%

***I rounded throughout this problem so go back and follow the steps using the correct amount of significant digits- and you should get something around there.

Answer 3

I cringe when I think of all of the time I spent in a Chemistry class.

Answer 4

steps are

1) find # moles of each reactant
2) find limiting reactant
3) based on limiting reactant, find theoretical yield of BaSO4
4) find % yield