дано

m(Zn) = 40 g

m(ppaH2SO4) = 80 g

W(H2SO4) = 8%

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V(H2)-?

M(Zn) = 65 g/mol

n(Zn) = m/M = 40 / 65 = 0.62 mol

m(H2SO4) = 80*8% / 100% = 6.4 g

M(H2SO4) = 98 g/mol

n(H2SO4) = m/M = 6.4 / 98 = 0.07 mol

n(Zn) > n(H2SO4)

Zn+H2SO4-->ZnSO4+H2

n(H2SO4) = n(H2)

V(H2) = n*Vm = 0.07 *22.4 = 1.57 L

ответ 1.57 л