Locating agents :
-chemical reaction/physical process
-colour
-temporary
-> thats why when the colors start to appear, we should quickly use a pencil to outline the spots.
Why pencil?
This is because the pencil mark will not break down and spread out as a dye, like an ink pen would.
Rf value:
distance travelled by spot
distance travelled by solvent
*Note! Rf must be in decimal, not fraction
What factors could affect the Rf value of a chemical?
-Adsorption
-High Solubility
-Choice of Solvent
-Choice of Stationary Phase
-Temperature
How is an Rf value useful?
We can compare Rf values of an unknown sample with Rf values of a known sample.
Chromatography is a system because it has certain fixed elements needed to be present such as, a solvent, a chromatography paper and a mixture. It also has certain rules needed to be followed and carried out so that the system can function.
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