Question

18 gram suatu zat non elektrolit dilarutkan dalam 250 air membeku pada suhu -0,744 C. kb = 1,86 c/m. tentukan mr zat tersebut m

Answer 1

Dik : massa = 18 gram, massa pelarut = 250 gram, Tf = -0.744 C, Kb = 1.86 C/m
Dit : Mr = ...
perubahan titik beku = 0 - (-0.744) = 0.744 C
^ Tb = molalitas x Kb
0.744 = 18/Mr x 1000/250
0.744 = 18/Mr x 4
0.744 = 72/Mr
Mr = 72/0.744
Mr = 96.7 ~ 97 gram/mol