CHM 1321 Study Guide - Silica Gel, Chemical Polarity, Elution

• School: University of Ottawa
• Department: Chemistry
• Course: CHM 1321
• Professor: All

Document Summary

Chromatography is a useful tool in chemistry and can be very helpful in determining the composition of an unknown sample. In chromatography there are two phases, a mobile phase and a stationary phase. The silica gel of the tlc plates is the stationary phase and the solvent is the mobile phase. Since silica gel is a very polar organic compound, polar molecules will move more slowly up the tlc plates than non- polar molecules. The solvent moves through the stationary phase through capillary action and draws the sample up with it. The different components will separate based on polarity and solubility leaving small dots that can be seen through the use of uv light. The distance these dots traveled through the silica gel divided by the distance the solvent traveled will give the rf values of the compounds. Extraction is also another important tool in chemistry used to separate compounds based on solubility.