AP Chem Food Dye Chromatography Minilab Name: Ben Wong
Background: Chromatography is a lab technique often used to separate out a mixture of substances using the concept “like dissolves like”, meaning things with similar polarity and intermolecular forces will dissolve in each other. There are two main components in a chromatography experiment: the stationary phase and the mobile phase. The stationary phase is a piece of paper that is stained with the chemicals one is trying to separate. The mobile phase is a solution that will move through the stationary phase, causing the stained chemicals to move with it. How far the chemicals move with the mobile phase is dependent on their polarity (how unevenly the electrons are shared in the molecule). If one is using a very polar…show more content… Look up the structures of red 40, red 3, yellow 5, and blue 1. Draw them on a piece of paper and draw some arrows to represent polar covalent bonds (with the arrow pointing to the electron dense part of the bond).
2. Based on their structure and polar covalent bonds, hypothesize an order of increasing polarity…show more content… The closer the Rf value is to 1, the more polar the substance
Ranking(from least polar to most polar): Red 3, Red 40, Yellow 5 ,Blue 1
Part 4: Use your chromatography paper for the unknown and identify the component dyes.
The black unknown dye appears to be made up of each dye. The green dye is comprises of the yellow 5 and blue 1 dyes. The pink dye contains the red 40, red 3, and blue 1 dyes. The unknown blue dye is merely blue 1 dye.
Part 5: Considering that water is extremely polar, what comments could you make about the other mobile
