Chromatography

Question 1

What is chromatography used for?

Answer 1

-used to separate a mixture into it’s individual components
-relies on different solubilities of different chemicals in a mixture

Question 2

How does chromatography work?

Answer 2

-components separate as the mobile phase travels over the stationary phase
-higher solubility = travels further up

Question 3

Method of putting mixture on paper

Answer 3

-spots of mixture are placed on paper
-left to dry
-suspended in a solvent
-as solvent travels up paper - different components move up paper at different speeds
-causes OG mixture to separate into different spots = chromatogram

Question 4

Separating monosaccharides

Answer 4

-mixtures already coloured don’t have to be stained
-spot is placed on the line - known spots are placed next to the sample
-suspended in a solvent
-unknown can be identified by comparing + matching with known solutions

Question 5

Separating amino acids

Answer 5

-spots of unknown placed to known
-known = lysine, alanine + methionine
-paper is suspended
-separate different distances - depending on charge + size
-can be compared to known
-same distance = contain this amino acid

Question 6

How to work out RF value?

Answer 6

-line drawn to show how far solvent has travelled from solvent front
-Rf value = how far a dissolved molecule travels during its mobile phase

Question 7

What does a smaller Rf value mean?

Answer 7

-smaller = less soluble - larger in size

Question 8

Rf value equation

Answer 8

-distance moved by solute/distance moved by solvent

Question 9

Identifying chloroplast pigments

Answer 9

-carotenoids = highest value
-chlorophyll B = lower Rf
-chlorophyll A = Rf between B + C