Lab 3B was performed in class on October 19. The objective of the lab was to identify the components of mixtures by means of there Rf values. It was fun to see how the food dyes separated into many colours.
Equipment:
3 Large test tubes
3 Erlenmeyer flasks
Ruler
3 pieces of chromatography paper
Food colouring ( yellow, red, or blue)
Green food colouring
Unknown mixture of food colouring
Water
Glass stirring rod
Procedure:
Part 1:
Students in groups of two, acquired 3 Erlenmeyer's flasks, and 3 Large test tubes. The test tubes were placed in the Erlenmeyer's flasks with two centimeters of water in each. A line was drawn across the chromatography paper, four centimeters from the end. The paper was then cut into a point from the pencil line.
Part 2:
Students received food colouring on there chromatography paper. One, of there choice, (red, yellow, or blue) one green, and one unknown mixture. The food colouring was placed on each paper via glass stirring rod, in spots. The first paper, the colour of your choice, was lowered into the first test tube so that about two centimeters were submerged. As the water climbed the chromatography paper, students made observations on the change in colour, the solute front, and the solvent front. After twenty minutes had elapsed, the paper was taken out, and a line was quickly drawn where the water had stopped climbing. After recording the solvent and solute fronts, the Rf values were recorded, and written on the board. All students copied down this information.
Part 3:
The unknown and the green food colouring was also placed in the test tubes. The same procedures as part 2 were then carried out up until the recording of the Rf values. Data was copied into table three in our notebooks.
Results:
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