Question
Sulfate Analysis
Show All Your Work for your sample below. Include in the table both your results and those of the person with whom you shared data. 1. Calculate the mass of BaSO_4 recovered (subtract the mass of the crucible from the mass of crucible plus BaSO_4) and record on line a: 2. Calculate the moles of BaSO_4 (using (1) and the molar mass of BaSO_4): 3. Calculate the moles of sulfate (SO_4^2-) ions using the result from (2) above: 4. Calculate the mass of sulfate in the unknown sample (using the moles of SO_4^2- from (3) above and the SO_4^2- molar mass) and record on line b. 5. Calculate the mass of the original unknown sample (subtracting the beaker mass from the mass of the beaker plus unknown) and record on line c: 6. Calculate the percentage (%) of the original sample that is sulfate (SO_4^2-) and record on line d: 7. Calculate the average percent sulfate combining the result of your trial with the result you calculated from your classmate's shared data and record on lin
Explanation / Answer
Question 1.
Mass of BaSO4 recovered:
18.26 g of BaSO4 + cruible - 17.555 g of crucible = 0.705 g of BaSO4
Question 2.
moles of BaSO4 --> mass of BaSO4/MW of BaSO4 = 0.705/233.38 = 0.003020 mol
Question 3.
moles of SO4-2 present..
ratio is 1 mol of BaSO4 = 1 mol fo SO4-2
so
0.003020 mol of BaSO4 = SO4-2 mol of 0.003020
Quesiton 4.
mass of unkown sample:
MW of SO4-2 = 96 g/mol
0.003020 mol --> 96*0.003020 = 0.28992 g of SO4-2