A sample of 0.6760 g of an unknown compound containing barium ions (Ba2+) is dissolved in water and treated with an excess of Na2SO4. If the mass of the BaSO4 precipitate formed is 0.1405 g, what is the percent by mass of Ba in the original unknown compound?

Answer 1

Ba^+2 + SO4^= -->BaSO4.

moles BaSO4 = g/molar mass = ??
moles Ba is the same as moles BaSO4.
g Ba = moles Ba x atomic mass Ba.
%Ba = (g Ba/mass original sample)*100 =??

Answer 2

3.45%

Answer 3

3.45