Unit C

Module 5 ~ Lesson 2

 Chromatography

In this experiment, liquid from crushed leaves is painted onto special paper. The paper is then placed in a test tube containing a solvent. The solvent is absorbed up through the paper and, as the solvent rises, it separates the different pigments. Generally, the pigments with the smallest molecules will move through the paper the fastest, but results may differ when some solvents or combinations of solvents are used. 

  1. Read the procedure on  pages 172-173  of your textbook in preparation for this online lab.
  2. To access the lab, go to this page.
  3. Follow the instructions in the lab and complete the quiz.
  4. Contact your teacher with any questions. Your lab activity does not need to be submitted to your teacher. Keep it for your notes and further study.

 Rf Values

Reference flow (R f  ) is a measure of how far a substance is transported in chromatography relative to the movement of the solvent used. It is calculated by dividing the distance a substance (pigment) moves by the distance the solvent moves.

 Self-Check

Below are the results of a chromatography experiment. If the solvent travelled 10.9cm and the pigment travelled 8.5cm, what is the Rf for the pigment (carotene)?