Question

Massa Ba(CH3COO)2 yang harus dilarutkan kedalam 100ml sehingga pH-nya = 9+log 2 adalah ka CH3COO = 2 x 10⁻⁵ Ar Ba=137 C=12 O=16 H=1 Help me please
a. 26,9 c. 38,5 e 52,1
b 29,7 d. 40,8

Answer 1

POH = 9 + log 2
= - log 2.10^-5
Mr Ba(CH3COOH)2 = (137 + ( 12x4 ) + ( 1x8 ) + ( 16x4))
= (137 + 48 + 8 + 64)
= 257

[OH-] = √Kw/Ka x m/Mr x 1000/v
2.10^-5 = √10^-14/2.10x m/257 x 1000/100
4.10^-10 = 5.10^-10 x 10 x m/257 (10^-10 di ruas kanan dan kiri sama-sama dicoret)
4 x 257 = 50m
1028/50 = m
20,56 gram = m