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Pertanyaan

Dik :v ch3cooh=10ml ,ph =3 diencerkan 90ml air ,Ka =1 × 10 min 5,ditanya ph yang berbentuk?

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  • 10 mL CH3COOH pH = 3
    + 90 mL air
    Ka = 1 × 10^-5

    pH yang terbentuk ... ?

    pH = 3
    - log [H^+] = 3
    [H^+] = 10^-3

    [H^+] = √( Ka × Ma )
    10^-3 = √( 10^-5 × Ma )
    (10^-3)^2 = (√( 10^-5 × Ma ) )^2
    10^-6 = 10^-5 × Ma
    Ma = 10^-6/10^-5
    Ma = 10^-1
    Ma = 0,1

    Konsentrasi awal larutan adalah 0,1 M

    V1 = 10 mL
    M1 = 0,1 M
    V2 = 10 + 90 = 100 mL
    M2 = belum diketahui

    V1 × M1 = V2 × M2
    10 × 0,1 = 100 × M2
    .......... 1 = 100 × M2
    .. 1/100 = M2
    .... 0,01 = M2
    ...... M2 = 0,01

    [H^+] = √( Ka × Ma )
    [H^+] = √( 10^-5 × 0,01 )
    [H^+] = √( 10^-5 × 10^-2 )
    [H^+] = √( 10^-7 )
    [H^+] = 10^-3,5

    pH = - log [H^+]
    pH = - log 10^-3,5
    pH = 3,5

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