Question

100 ml larutan NaOH 5M. jika Mr NaOH=40 , H2O=18 dan massa jenis larutan NaOH=1,10 gr/ml tentukan fraksi mol larutan NaOH

Answer 1

Mol NaOH = M.V
                = 5.0,1 = 0,5 mol
massa NaOH = mol x Mr = 0,5 x 40 = 20 gram

massa larutan = ρ.V = 1,1 x 100 = 110 gram
massa Air = massa larutan - Massa air
               = 110 - 20
               = 90 gram

mol NaOH = 0,5 mol
mol air = gr/Mr = 90/18 = 5 mol
mol larutan = 5 + 0,5 = 5,5 mol

Frkasi mol NaOH