1. Paper Chromatography
And Rate of Flow

2. What is Chromatography?
Chromatography is a useful method for separating mixtures.
The components of a mixture are not chemically combined (or bonded). Therefore, they can be separated.

3. What is Chromatography?
Many mixtures, such as food coloring and ink, consist of two or more dyes blended together.
After completing a paper chromatography, you will see a pattern of colors appear.
Each color or shade of color will be a single component of the whole mixture.
These dyes dissolve at different rates.

4. Why do the Dyes Separate
These dyes dissolve at different rates because of their densities and size.
The smaller the dye size the further it will travel
How will these rocks be arranged after the fireman turns on his hose FULL BLAST?
Direction of Flow

5. What about the distance traveled?
The distance that a component travels is a property of the dye and the solvent (the liquid that is dissolving the ink).
This distance is unique for each dye in each solvent. (as long as you use the same solvent, the dye will always travel at the same rate.)

6. Rate of Travel
The rate at which the components travel from the Origin to the Finish Line is call the Rate of Flow. (It is abbreviated as Rf ).
Finish Line
Origin

7. How to Calculate Rate of Flow
Find the center of each component of the dye and mark it on the paper. 4 3 2 1 5
Measure the distance from the Origin to the center of each component of the dye.
Finish Line
Origin
Measure the distance from the Origin to the Finish Line

8. How to Calculate Rate of Flow
Calculate the rate of flow for each component by using the following formula:
Distance the component traveled Rf =
Distance to the Finish Line
The Rf will always be less than or equal to one.
If the component of the dye is found closer to the Finish line, the Rf will be closer to the number ONE
If the component of the dye is found closer to the Origin line, the Rf will be closer to the number ZERO

9. Practice Problem 3.45 cm Rf 0.67 5.15 cm 3.45 cm 5.15 cm
Distance from the Origin to the Center of Dye component =
3.45 cm
Distance from the Origin to the Finish Line =
5.15 cm
3.45 cm Rf
0.67 = =
5.15 cm