Purification and Property Determination

Isolating your Compound

Separate Mixtures

Before properties can be determined pure compounds must be isolated. If the starting point is a mixutre then the mixutre must be separated. Before properties can be accuratly determined the compound must be free of inpurites.

Mixtures of liquids are separated by distilation. Mixtures of solids are separated using differing solubilities in Ether, Base, and Acid.

Remove Impurities

Purification is the removal of impurities. Liquids are purified using distilation, while as solids are purified using recrystalization

Compounds must be free of impurities to obtain accurate measurments!

Determine Phase Change Temperatures


Boiling points (BP) are determined as the maximum temperature before the sample is completly vaporized during distilation

Thermometers have a lag time, so substance may be fully evaporated before the thermometer has a reading


Melting points (MP) are determined after recrystalized crystals are completly dry (usually 2 days after recrystalization) in the MelTemp device

Determine Index of Refraction


Use the refractometer (using manufacturer's guidelines) to determine the index of refraction (RD) on freshly distilled liquid sample.

To read the refractometer you must ajust the focus of the black horizon, afterwards you center it in the crosshairs.


Solids do not have refractive indexes.