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Pertanyaan

sebanyak 1 liter larutan CH3COOK mempunyai pH = 8 . jika Ka CH3COOH = 10^-5 dan Mr CH3COOK =98, massa garam CH3COOK yang terlarut dalam 1 liter larutan CH3COOK sebanyak ... mg
a. 49
b. 98
c. 147
d. 198
e. 255

1 Jawaban

  • pOH = 14 - 8 = 6
    pOH = - log OH-
    6 = -log OH-
    OH- 10^-6

    OH- = √ kw / ka x Mg
    10^-6 = √ 10^-14 / 10^-5 x Mg
    10^-12 = 10^-9 x Mg
    Mg = 10^-3 M = 0.001 M

    Mg = n / V
    0.001 M = n / 1 L
    n = 0.001 mol

    massa = n x Mr
    massa = 0.001 x 98
    massa = 0.098 gr = 98 mg

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