Jawabanmu

2013-12-15T09:00:59+07:00
M =  \frac{mol}{volume}
mol = M . Volume
mol = 2 . 0,25 = 0,5

Mr NaOH = Ar Na + Ar O + Ar H = 23 + 16 + 1 = 40

massa = mol . mr = 0,5 . 40 = 20 gram
2013-12-15T09:02:08+07:00
M = gr/Mr x 1000/vol
2 = gr/ Mr x 1000/250
2 = gr/Mr x 4
2/4 = gr/Mr
Mr NaOH = 23+16+1= 40

jadi, 2/4= gr/40, gr=20 gr.