The purpose of this lab was to identify and calculate the Ratio of Fronts for 3 given solutions. The solvent and solutions in this case are water and food colouring respectively.
Using paper chromatography, we identified which base colours were in each of the dye.
First, we cut out 3 strips of paper measuring 22cm x 2.5cm.
Then, we measure 4cm from one end and draw a line in pencil, and then trim that part into a point. The sample spot goes on the pencil line.
After, we put the labelled strips of paper with the food colouring into the test tube, with water only reaching up to about half of the point. Check on it after 10 min.
Finally, after 20 min since we put them in, we take the strips of paper out of the test tubes and identify the solute front and the solvent front. Draw a pencil line to show the solvent front.
Experiment 1 resulted in a single colour, and the others in multiple colours.
To solve for the ratio of fronts:
Rf = d1 / d2
Where:
Rf is the ratio of fronts
d1 is the distance traveled by solute
d2 is the distance traveled by solvent
For example:
If the solution traveled 7.3cm from the sample line, and the solvent traveled 7.5cm from the sample line:
Rf = 7.3 / 7.5
Rf = 0.97
0.97 is close to Blue #1 on the Table for Some of the Dyes Approved for Food Colouring
By: Jason Zhang
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