chromatography lab
...e solvent is drawn up, those substances that are not adsorbed by the paper will move at the same rate as the solvent. Substances that are bound very tightly to the paper will not move very far. Substances that interact weakly with the paper will move, but more slowly than the solvent. This difference in migration rates up the paper causes the components of the substance to be separated at different points on the paper. The separation also happens because the different pigment molecules have a different size and mass, so the heavier ones cannot travel up as much or as quickly. Also, each pigment has a different charge and is therefore pulled at a different rate. 2. The dark yellow pigment migrated furthest up the paper. This means that it did not form bonds with the paper and is the pigment that is the most soluble in the solvent. It also could indicate that the molecules of the pigment are small and have a small mass. The lighter yellow and the darker green pigments travelled mid- way up. This means that these pigments bonded to the paper more so than the dark yellow pigment. It also means that these molecules are heavier and larger in size than the molecules in the light yellow pigment. The light green pigment travelled the least. This means that this pigment formed very strong hydrogen bonds with the paper and is therefore very polar. It also indicates that the molecules of this pigment are the heaviest and largest and therefore are difficult to move up the paper. This pigment was also the least soluble in the solvent. 3. The four pigments that we separated were: Chlorophyll A, the darker shade of green; chlorophyll B, the lighter shade of green; Carotene, the darker shade of yellow; Xanthophyll, the lighter shade of yellow. 4. In the fall, leaves turn shades of yellow. This is because the leaves stop producing green chlorophyll and it disappears. As the bright green fades away, we begin to see the yellow and orange colours that were covered up by the green chlorophyll. Sources of Error: It is very difficult to come up with accurate exact results by analyzing chromatography paper. It is difficult to determine exactly where one colour ends and another starts. There may have been anomalies in the paper or uneven zones due to unequal placement of the leaf pigment on the paper. Another possible source of error is the amount of solute applied caused the solution became near ...