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Pertanyaan

larutan CH3COONa sebanyak 10 ml memiliki ph=8 jika ka 1 x 10^5 garam CH3COOH yang berlarut dalam 200 ml lanjutannya sebanyak (Ar c=12, H=1 O=16,Na=23)

1 Jawaban

  • pH = 8, pOH = 14-8 = 6, [OH^-] = 10^min6
    [OH^-] = √(Kw/Ka) x Mgaram
    Mgaram = [OH^-]^2 x Ka/Kw
    = (10^min6)^2 x 10^min5/10^min14
    =0,001 molar
    M = mass/Mr x 1000/mL
    0,001 = mass/82 x 1000/100
    Mass = 82/10000 g = 8,2 mg

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