Question

Tentukan fraksi mol zat terlarut dan zat terlarut :

a. larutan 10% NaOH dalam air
b. larutan 1 molal glukosa

Answer 1

NaOH 10% = 10 gram
Air 90% = 90 gram

mol NaOH = gr/Mr = 10/40 = 0,25 mol
mol Air = gr/Mr = 90/18 = 5 mol
mol larutan = 5 + 0,25 = 5,25 mol

fraksi mol zat terlarut


 fraksi mol pelarut
1 - 0,048 = 0,952



b.
1 molal = 1 mol glukosa dalam 1000 gram air

mol glukosa = 1 mol
mol air =gr/Mr = 1000/18 = 55,56 mol
mol larutan = 1 + 55,56 = 56,56 mol

fraksi mol zat terlarut


fraksi mol pelarut
1 - 0,018 = 0,982