1,5 gram urea (Mr =60) dilarutkan dalam 500gram air (Mr=18) hitunglah titik didih dan titik bekunya! diketahui kf air = 1,86°C/m dan kb air = 0,51°C/m

wt = 1,5 gram
Mr = 60
wp = 500 gram
Kb = 0,51°C
Kf = 1,86°C
Kb = ...?
Kf = ...?

m = wt/Mr x 1000/wp
= 1,5/60 x 1000/500
= 0,05

∆Tb = m.Kb
= 0,05 x 0,51
= 0,026

Tb = Tb° + ∆Tb
= 100 + 0,026
= 100,026°C

∆Tf = m.Kf
= 0,05 x 1,86
= 0,093°C

Tf = Tf° - ∆Tf
= 0 - 0,093
= -0,093°C