Faculty of Chemical Engineering and Technology,Zagreb
People involved in this project:
Magdalena Pavljak, KIM
Elvira Pek, KIM
Elena Vlačić, KIM
Boris Vučić, KIM
The purpose of the experiment:
Determine the molecular weight of an unknown organic compound.
Instruments needed for the experiment:
• internal pot
• external pot with the ester
• measuring burette
• leveling pot
• metal cylinder
• 2 ampoules
• propylene glycol ester
• organic solution
Metal cylinder, which serves as thermal isolation, should be put on a tripod with the asbestos mesh. Attach the external pot with the ester within the cylinder. Dry out the internal pot and place it inside the external pot, and secure it in place with a cork so that the internal pot is placed above the ester level in the external pot. Internal pot must then be connected with the leveling pot.
Once the apparatus is prepared, it can be heated.
Trim the ampoules according to the apparatus, and then weigh them on an analytic scale.
First ampoule should be heated and then immersed in the sample vial. When ampoule is filled to half, fuse its top, and weigh it again.
When apparatus is heated enough, place the magnet through the opening, put a plug in it and attach an electromagnet connected with inducer on the outter side of the opening. Through the second opening, place a prepared ampoule loaded with a nut wrench,and put a plug in it too.
By raising and lowering the leveling pot,we are setting up the initial volume of the burette (preferably as small as possible)
By pushing the buttons on the transformer, the electromagnet pulls in the magnet in the external pot, which causes the loaded ampoule to fall to the bottom of the internal pot and break. The sample evaporates and the resulting vapor ejection is equal to the volume change in the leveling pot and the burette. The volume is stabilized by lowering the leveling pot next to the burette. When the volume is stabilized, we read off the final value of the volume.
The mesurement is repeated once again as described.
Result and conclusion:
This experiment helps us to determine the mass and the volume of the organic compound, in the known pressure and temperature conditions. Using those information, we are able to calculate the molar mass of our sample. By comparing the experimental molar mass and the theoretical molar mass, certain disimilarities are visible between the two. Regarless of the small disimilarities, we can conclude that the Victor Meyer method is very reliable.