Ответ:

дано

m ppa (CH3CH2COOH) = 50 g

W(CH3CH2COOH) = 7.4 %

W(NaOH) = 20%

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m ppa (NaOH) -?

m(CH3CH2COOH) = 50*7.4 % /100% = 3.7 g

CH3-CH2-COOH+NaOH-->CH3-CH2-COONa+H2O

M(CH3CH2COOH) = 74 g/mol

n(CH3CH2COOH) = m/M = 3.7 / 74 = 0.05 mol

n(CH3CH2COOH) =n(NaOH)

M(NaOH) = 40 g/mol

m(NaOH) = n*M = 0.05 * 40 = 2 g

m(ppa NaOH) = 2*100% / 20% = 10g

ответ 10 гр.

Объяснение: