mohon bantuanya ya, kak butuh banget... Nomer 127, dan 1 25. makasih

Kelas      : XI
Kategori : Kelarutan & Hasil Kali Kelarutan

#Menghitung kelarutan
Misalkan kelarutan = s (mol/liter)

[No.125]
Mg(OH)₂ → Mg²⁺ + 2 OH⁻
     s              s            2s

Ksp = [Mg²⁺] [OH⁻]²
        = [ s ] [ 2s ] ²
        = 4s³
s = ∛ [Ksp/4]
   = ∛ [(3,2 x 10⁻¹¹)/4]
   = ∛ [8 x 10⁻¹²]
Jadi kelarutan = 2 x 10⁻⁴ mol/liter

Mr Mg(OH)₂ = 24 + 2(16 + 1) = 58
Massa Mg(OH)₂ = mol x Mr
                          = 2 x 10⁻⁴ x 58
Jadi kelarutan = 0,0116 gram/liter

[No.127]

(a)
AgIO₃ → Ag⁺ + IO₃⁻
    s           s        s

Ksp = [Ag⁺] [IO₃⁻]
       = [ s ] [ s ]
       = s²
s = √ [Ksp]
   = √ [4 x 10⁻¹²]
Jadi kelarutan = 2 x 10⁻⁶ mol/liter

(b)
Ag₂CrO₄ → 2 Ag⁺ + CrO₄²⁻
      s               2s         s

Ksp = [Ag⁺]² [IO₃⁻]
       = [ 2s ]² [ s ]
       = 4s³
s = ∛ [Ksp/4]
   = ∛ [(3,2 x 10⁻¹⁶)/4]
   = 4,3 x 10⁻⁶
Jadi kelarutan = 4,3 x 10⁻⁶ mol/liter

(c)
Al(OH)₃ → Al³⁺ + 3 OH⁻
     s            s          3s

Ksp = [Al³⁺]² [OH⁻]³
       = [ s ] [ 3s ]³
       = 27s⁴
s = \⁴/ [Ksp/27]
   = \⁴/ [(2,7 x 10⁻¹²)/27]
   = 5,62 x 10⁻⁴ mol/liter
Jadi kelarutan = 4,3 x 10⁻⁶ mol/liter