in the gravimetric determination of barium in BaCrO4, what weight of sample must be taken so that the weight of the precipitate in milligrams multiplied by 100 will equal the % Ba in the sample?

Answer 1

[mass BaCrO4 ppt x (atomic mass Ba/molar mass BaCrO4)/mass sample)]*100 = %Ba

For mass BaCrO4 substitute the following:
(mg BaSO4 x 100/1000) into the top equation and solve for mass sample.

Post your work if you get stuck.