STOIC %YIELD

NOT ANOTHER STOIC PROBLEM

1) Barium sulfate, BaSO4, is made by the following reaction:


Ba(NO3)2(aq) + Na2SO4(aq) à BaSO4(s) + 2NaNO3(aq)
An experiment was begun with 75.00g of Ba(NO3)2 and an excess of Na2SO4. After collecting and drying the product, 63.45g BaSO4 was obtained. Calculate the theoretical yield and percent yield of BaSO4.



2) Aluminum sulfate can be made by the following reaction:
2AlCl3(aq) + 3H2SO4(aq) à Al2(SO4)3(aq) + 6HCl(aq)
It is quite soluble in water, so to isolate it the solution has to be evaporated to dryness. This drives off the volatile HCl, but the residual solid has to be treated to a little over 200°C to drive off all the water. In one experiment, 25.0g of AlCl3 was mixed with 30.0g H2SO4. Eventually, 28.46g of pure Al2(SO4)3 was isolated. Calculate the percent yield.

ANSWERS:

1.) theoretical yield = 66.98g BaSO4, % yield = 94.73%
2.) % yield = 88.74%