Jawabanmu

2014-09-11T23:46:34+07:00
Pertama, cari massanya dulu
m = p v = 1,25 * 800 = 1000 gr,, berarti massa totalnya 1000gr
lalu cari mol si Ca(OH)2 
M =n/v
n = M . V = 0,5 * 0,8 = 0,4 mol
mol = gr / mr
0,4 = gr / 74
gr = 0,4 * 74 = 29,6 gr

massa total = Massa ca(OH)2 + Massa air
1000 = 29,6 + m air
m air = 970.4 gr

Fraksi mol Ca(OH)2 = mol ca(oh)2 / mol ca(oh)2 + mol air

= 0,4 / 0,4+ 970,4:18
= 0,0074
=74*10^-4
= 7,4 * 10^-3
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