Numerical answer type, answer in g, tolerance 0.01.
Answer: 70.56 g
Pure FeS2 = 60.0 x 0.800 = 48.0 g; molar mass 120, so n = 0.40 mol. Each FeS2 supplies 2 S, so 2 x 0.40 = 0.80 mol S. With 90.0% yield n(H2SO4) = 0.720 mol. Mass = 0.720 x 98 = 70.56 g.