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
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.
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.
To calculate the mass of sulfate in a 0.7g sample of alum, you need to use the molar ratio between barium sulfate (BaSO4) and sulfate (SO4). Here's how you can do it:
1. Find the molar mass of BaSO4. Ba has a molar mass of 137.33 g/mol, S has a molar mass of 32.07 g/mol, and O has a molar mass of 16.00 g/mol. Adding them up, the molar mass of BaSO4 is 137.33 + 32.07 + (16.00 x 4) = 233.37 g/mol.
2. Calculate the moles of BaSO4 in the 0.46g sample. Divide the mass of BaSO4 (0.46g) by the molar mass of BaSO4 (233.37 g/mol): 0.46g / 233.37 g/mol = 0.00197 mol BaSO4.
3. Use the molar ratio between BaSO4 and SO4 to find the moles of sulfate in the 0.00197 mol of BaSO4. The balanced chemical equation for alum is Al2(SO4)3. For every 1 mole of BaSO4, you have 1 mole of SO4. Therefore, the number of moles of SO4 is the same as the number of moles of BaSO4. So, 0.00197 mol BaSO4 is equivalent to 0.00197 mol SO4.
4. Finally, calculate the mass of sulfate in the 0.7g sample of alum. Multiply the number of moles of SO4 (0.00197 mol) by the molar mass of SO4 (96.06 g/mol): 0.00197 mol x 96.06 g/mol = 0.192 g SO4.
So, the mass of sulfate in the 0.7g sample of alum is 0.192 grams.