Jawabanmu

2014-05-13T20:23:44+07:00
Ca(OH)2 = basa kuat

pH = 10 + log 4,
maka pOH = 4 - log 4, [OH^-] = 4 x 10^-4

[OH^-] = valensi basa x M basa
4 x 10^-4 = 2 x M
4 x 10^-4/2 = M
2 x 10^-4 = M

V = 500ml = 0,5 liter

M = n/V
2 x 10^-4 = n/0,5
2 x 10^-4/0,5 = n
4 x 10^-4 = n

Ca(OH)2
Ca= 40, H=1, O=16).
Mr = 40 + (2 x 16) + (2 x 1) = 40 + 32 + 2 =74

n = massa /Mr
4 x 10^-4 = massa/74
296 x 10^-4 = massa
2,96 x 10^-2 = massa

Jadi, massa Ca(OH)2 adalah 2,96 x 10^-2 gram
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