paper chromatography

what is chromatography used for?

chromatography is used to separate and identify coloured compounds in mixtures such as inks, paints, and foods

what is paper chromatography?

paper chromatography is a simple technique that separates substances based on how well they dissolve in a solvent

why do substances separate in paper chromatography?

different substances dissolve in the solvent at different rates, causing them to move at different speeds along the paper

what is the mobile phase in chromatography?

the mobile phase is the solvent that moves along the paper, carrying the dissolved substances

what is the stationary phase in chromatography?

the stationary phase is the paper through which the solvent and dissolved substances move

what is a chromatogram?

a chromatogram is the paper with the separated components of a mixture after chromatography

what is the formula for calculating the Rf value in chromatography?

Rf = (distance moved by the spot) ÷ (distance moved by the solvent)

how are the distances measured when calculating the Rf value?

both the compound’s movement and the solvent’s movement are measured from the starting position of the sample on the paper

what does the Rf value represent in chromatography?

the Rf value shows how far a compound moves relative to the solvent, helping to identify different substances.

does the Rf value of a compound change under the same chromatography conditions?

no, the Rf value remains the same if the chromatography conditions, such as solvent and temperature, do not change.

uses of paper chromatography

• distinguishing between pure and impure substances

• identifying substances by comparing the pattern on the chromatogram with the patterns formed by known substances

• identifying substances by calculating their Rf values