Abstract:

The experimental device of the physical chemistry experiment "Determination of the molar mass by freezing point depression" was innovatively improved to overcome the problems of the existing devices. A metal cold trap cooled by semiconductor chilling plates and a freezing point test tube integrated turbine agitator and heater were designed; a precise temperature measurement circuit was built. And each part was integrated into a complete set of equipment. The improved device was applied to the measurement of the urea-water, sucrose-water and naphthalene-cyclohexane systems. The results show that compared with the existing experimental device, the improved device has better repeatability, higher accuracy, higher experimental efficiency, and is more in accord with the needs of laboratory teaching. And it is more beneficial to cultivating the innovative thinking and scientific research ability of students.

Key words: Freezing point depression, Molar mass, Improvement of laboratory equipment