Hitunglah fraksi mol urea dalam larutan urea 20 persen

mol  urea= gr/mr = 20/60=0,33
mol air= gr/mr = 80/18=4,44

Xurea = mol urea/mol urea + mol air
           = 0,33/0,33+4,44
           =0,33/4,77
           =0,069