C2 Chemistry - paper and gas chromatography Flashcards Preview

Science B2 C2 P2 > C2 Chemistry - paper and gas chromatography > Flashcards

Flashcards in C2 Chemistry - paper and gas chromatography Deck (9)
Loading flashcards...

what is paper chromatography?

used to separate mixtures of coloured compounds


what are the mixtures suitable for chromatography?

inks, dyes and colouring agents in foods


what happens in paper chromatography?

spot of mixture on paper
paper placed in solvent
solvent soaks up the paper
carries mixture with it
different components of the mixture move at different rates


what are RF values?

separated components of the mixtures can be identified by calculating the RF values


how do you calculate the RF values?

distance moved by the components divided distance moved by the solvent


what is gas chromatography?

allows a mixture of compounds to be separated


what is the tube used in GC called?

a column


explain the process of GC
(5 steps)

1. sample dissolved in solution
2.put in one end of the column
3. unreactive gas carries sample through column
4.different substances travel at different times, becoming separated
5. separated substances leave at different times, and are detected by a detector


what is retention time?

the time taken for substance to pass through column