Dr. Fathia Mohammed Ibrahim
Abstract: In this work, the molecular weight of synthetic sugar were determine by measuring the freezing point of a solution and then comparing the freezing point of that solution to that of the pure solvent (water).Solutions of synthetic sugars were prepared by adding 0.5g to water. The freezing point of the solutions were recorded when the first ice crystals appear. Then the molecular weight of synthetic sugars was calculated (table), using the freezing point depression (Tf=Tf, pureTf, solution) andKF is themolal freezing point depression constant, (for water = 1.853 Kkg/mol ), these values were used to determine the molality of solution and the molecular weightas equations illustrate Tf= (Kf) (m). The molecular weights of prepared synthetic sugar weredetermined and it was found to be (205, 232, 272, 310, 323 and 355) (table).The molecular weight of synthetic sugar has the same numerical value as its molar mass.
Keywords: Colligative properties, freezing point depression, molecular weight, molar mass, molality