How to Identify Organic Compounds by Melting Points
- 1). Determine the melting point of an unknown organic compound. This value may be provided to you by your teacher, or you can determine it using a melting-point apparatus. If measuring the melting point yourself, repeat the measurement three times and calculate the average melting point.
- 2). Create a list of compounds with a melting point similar -- within one or two degrees -- to that of the unknown sample. Refer to a chemical reference manual or online melting point database for melting point information.
- 3). Eliminate compounds from the list that do not match the other known characteristics of the unknown sample. For example, if the melting point of an unknown sample matches that of two compounds -- A and B -- but the molecular weight of B is significantly higher than that of the unknown, then B can be eliminated.
- 4). If multiple compounds still remain on the list, obtain from your teacher -- or measure -- additional information about the unknown sample. Look for characteristics that will eliminate compounds from the list. For example, if the remaining compounds have similar molecular weights but different boiling points, then measure boiling point.
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