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Ответ:

дано

m(ppa NaOH) = 200 g

W(NaOH) = 20%

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m(H2SO4) -?

m(NaOH) = 200*20% / 100% = 40 g

2NaOH+H2SO4-->Na2SO4+2H2O

M(NaOH) = 40 g/mol

n(NaOH) = m/M =40 / 40 = 1 mol

2n(NaOH) = n(H2SO4)

n(H2SO4) = 1 / 2 = 0.5 mol

M(H2SO4) = 98 g/mol

m(H2SO4) =n*M  =0.5  * 98 = 49 g

ответ 49 гр

Объяснение: