J.R. S. answered 11/15/19
Ph.D. University Professor with 10+ years Tutoring Experience
Ba(NO3)2 + Na2SO4 ==> BaSO4 + 2NaNO3 ... balanced equation
Theoretical yield of BaSO4 from 0.45 moles of Ba(NO3):
0.45 moles Ba(NO3)2 x 1 mol BaSO4 / mol Ba(NO3)2 = 0.45 moles BaSO4
Percent yield = actual yield / theoretical yield (x100%) = 0.41 mol / 0.45 mol (x100%) = 91 %