For the determination of molar masses of dissolved substances by lowering the freezing point (cryoscopy). The apparatus comprises two cylindrical glass vessels which are placed inside each other. The outer vessel consists of a closed glass tube with a GL 45/32 threaded glass fitting and a round bottom. The inner vessel is also closed but has a flat bottom. At the upper end there is a threaded glass fitting GL 25/10. Below this fitting there is a slanted opening on the side with a threaded glass fitting GL 18 with a sealing cap.
To measure freezing point depression, the two vessels are placed inside each other and screwed together tightly. The outer vessel is filled with a liquid for heat transport (e.g. ethanol). The inner vessel holds the selected solvent. A temperature measuring device (thermometer or electronic thermosensor) is attached in the upper glass threaded fitting.
The device assembled in this way is placed in a container with a refrigerant mixture and the freezing point of the solvent is determined.
A second freezing point determination is carried out after a sample of the substance to be tested, pressed into a pill, has been added to the solvent in the inner vessel. From the measured freezing point depression and the mass of the added substance, the molar mass of this substance can be determined.
Equipment and technical data
made of DURAN
Dimensions of the outer vessel:
Diameter: da = 44 mm
Total length: l = 180 mm
Dimensions of the inner vessel:
Diameter: da = 32 mm
Total length: l = 220 mm
To measure freezing point depression, the two vessels are placed inside each other and screwed together tightly. The outer vessel is filled with a liquid for heat transport (e.g. ethanol). The inner vessel holds the selected solvent. A temperature measuring device (thermometer or electronic thermosensor) is attached in the upper glass threaded fitting.
The device assembled in this way is placed in a container with a refrigerant mixture and the freezing point of the solvent is determined.
A second freezing point determination is carried out after a sample of the substance to be tested, pressed into a pill, has been added to the solvent in the inner vessel. From the measured freezing point depression and the mass of the added substance, the molar mass of this substance can be determined.
Equipment and technical data
made of DURAN
Dimensions of the outer vessel:
Diameter: da = 44 mm
Total length: l = 180 mm
Dimensions of the inner vessel:
Diameter: da = 32 mm
Total length: l = 220 mm
Properties
- P3682100
- 36821-00