дано

m(H2SO4) = 40 g

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m(BaSO4)-?

H2SO4+BaCL2-->2HCL+BaSO4↓

M(H2SO4) = 98 g/mol

n(H2SO4) = m(H2SO4) / M(H2SO4) = 40 / 98 = 0.41 mol

n(H2SO4) = n(BaSO4) = 0.41 mol

M(BaSO4) = 233 g/mol

m(BaSO4) = n(BaSO4) * M(BaSO4) = 0.41 * 233 = 95.53 g

ответ 95.53 г