Answer to Question #55916 in General Chemistry for jocelyn
if some of the solid precipitated were actually SrSO4 instead of BaSO4, would the final calculated percentage sulfate be higher or lower than the actual value?
First possibility. If you use Strontium in precipitation reaction, solubility of strontium sulfate is higher than for barium sulfate and higher amount of sulfate ions will stay in solution. So, you will get lower percentage than actual. Second possibility. If you use the molar weight of BaSO4 for the mixture of SrSO4 and BaSO4, you will get the lower quantity of sulfate ions than real, as molecular weight of SrSO4 is lower than for BaSO4. In this case, obtained percentage of sulfate ions also will be lower than actual value.