Paper Chromatography and Rf Values | GCSE Chemistry
Chromatography is used to separate and identify substances based on their solubility.
How do you calculate the Rf value of a substance?
What is Paper Chromatography and Rf Values | GCSE Chemistry?
"An analytical technique used to separate and identify substances in a mixture based on their distribution between a mobile phase and a stationary phase."
What color flame does a Sodium (Na+) ion produce?
A student sees a lilac flame during a test. Which ion is present?
Why can a flame test be unreliable if the sample is a mixture of ions?
Separating Ink
Stationary phase: The paper.
Mobile phase: The solvent (e.g. water or ethanol).
Rf = distance moved by substance / distance moved by solvent.
A pure substance produces a single spot in all solvents.
Practical Point: Always draw the baseline in PENCIL because ink would dissolve and ruin the chromatogram.
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