Chromatography Lab
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Date:
1. What is Chromatography?
2. What is a retention factor (Rf)value)?
3. Calculate the Rf values for the primary color and mixtures of color.
Color
Solute distance
Solvent distance
Blue
Yellow
Red
Green
Orange
Black
4. What color was the most soluble?
5. What color was the least soluble?
6. What colors make green?
7. What colors make orange?
8. What colors make black?
9. What can chromatography be used for? (2 examples.)
Rf value
Name:
Date:
Chromatography Lab
Background: Solutions may contain a mixture of solutes. Each solute has a different ability to dissolve.
Each solute has a mobile and stationary phase when dissolved in a particular solvent will be deposited
on chromatography paper at different distances when carried by the solvent front. The distances can be
measured and analyzed using a retention factor calculation:
Rf = Solute Distance (cm)
Solvent Distance (cm)
Each substance has a unique Rf value that can be used to identify the substance in an unknown sample.
Procedure: USE PENCIL ONLY!
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Measure a piece of chromatography paper 10.5 cm. x 7.5 cm.
Mark a dot on the edge 1.5 cm. from the bottom. On each side of the paper.
Draw light line across the chromatography paper 1.5 cm. from the top.
Using your bottom line, measure 1.5cm from the left side of the paper, place 6 dots 1.5cm
apart.
Obtain 6 colors of dye in a well plate. One drop of each.
Using a tooth pick apply one drop of each color at each of six dots on the bottom of the page.
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Red
Yellow Blue Orange Green Black
Prepare the solvent chamber.
Using a 400ml beaker add 15mL of 1.0% NaCl solution
Cut a piece of aluminum foil to cover the top of the beaker.
Place the chromatography paper in the solvent chamber and cover with the foil. Leave one
opening to allow the solvent to wick through the paper.
DO NOT TOUCH or SPIN the beaker.
When the first solute reaches the top line remove the chromatography paper from the chamber
and place on a paper towel to dry.
Clean up other materials
Trace the solvent front lightly with pencil.
Calculations: See the report sheet.