paper chromatography Flashcards
In paper chromatography, mixtures of soluble substances are?..
separated
what’s a solvent (mobile phase) run through?- in paper chromatography.
the mixture on the paper- containing the stationary phase.
do the substances on the paper in paper chromatography move at the same or different rates?
different rates.
which substance moves furthest up the paper in paper chromatography?
The most soluble substance will move the furthest up the paper.
What is the mobile phase in paper chromatography?
a solvent
What is the stationary phase in paper chromatography?
chromatography paper
what do we use to identify compounds in mixtures by calculating Rf values?
chromatograms
what produces chromatograms?
chromatography
Rf Values equation->
Rf= distance travelled by substance/ distance travelled by solvent
what’s a reference substance?
a pure sample that’s run alongside the unknown mixture to see if it’s a component in the mixture.
what do Rf values depend on?
the solvent
where can we learn more about the identity of the components?
by testing any references and the unknown mixture in a range of solvents
what does the practical for paper chromatography investigate in?
separating mixtures
whats the pencil used for at the start of a chromatography practical and why?
to draw a horizontal line near the bottom of the chromatography paper and this is because if you used a pen the ink would run down the paper in the solvent.
what do you put on the start line in the practical?
On this ‘start line’, put samples of known food colourings (A - D) alongside an unknown substance (X)
In paper chromatography, the components that travel furthest are?..
the highly soluble ones in the solvent and those that are minimally attracted to the chromatography paper.
What can we say if the Rf values of a reference and a spot match in all solvents?
it’s very likely that the mixture contains the reference compound.
apparatus needed for chromatography practical->
beaker, solvent and chromatography paper.
