Dik: 500 ml lar urea 2M

a. karena dalam 500 ml lar ada 2 M urea
maka mol urea = 2x0.5 =1 mol
massa 1 mol urea = 1x60 = 60 gr      (Mr urea =60)
maka massa air = 500 x 1.2 -60 = 540 gr
m = 1 mol urea : 0.54 = 1,852 molal

b.x urea = n urea :n (air + urea)
=1:(30+1)
=0.03226

c. xpelarut = n air : n (air + urea)
= 30 : 31
=0.96774