posted by Zachary .
Based on the mass of barium sulfate (0.46g), calculate the mass of sulfate in a 0.7g sample of alum.
I think I did this right but i'm not sure.
0.46g BaSO4/233.37g BaSO4=0.002mol BaSO4
0.002mol BaSO4 x 1mol SO4/1molBaSO4=0.002molSO4
I don't understand the question. You calculated mols only, not grams.
I can calculate g sulfate or I can calculate grams sulfate in a 0.7 g sample of alum but I don't understand what the two have to do with each other.
In the second half of the experiment 3mL of hydrochloric acid and 30mL of barium chloride were reacted with a 0.7g sample of alum to get barium sulfate.
The question says based on the mass of barium sulfate (0.46g), calculate the mass of sulfate in your sample of alum.
Then you have done it right for mols but you didn't calculate sulfate. And the 0.7 g alum doesn't have anything to do with the problem (unless you wanted to calculate percent sulfate in the sample).
I obtained 0.00197 mols BaSO4 which is 0.00197 mols SO4 and that x 96.064 = g sulfate. That gives me 0.189 g which if tghe 0.46 is all of your number, then I would round the 0.189 to 0.19g.