paper chromatography

Question 1

what is paper chromatography?

Answer 1

is a method used to separate mixtures of soluble substances.

Question 2

what are the two phases of paper chromatography and what do they do?

Answer 2

stationary phase - solvent are on the paper and do not move through it. It is uniform and adsorbent on paper

mobile phase - is the solvent that moves through the paper, carrying different substances with it

Question 3

what is the method of paper chromatography?

Answer 3

1. a horizontal line is drawn one end of the paper
2. the sample is placed as a small drop on to the paper using a capillary tube
3. the paper is then placed into a container with a solvent below the sample drop
4. the solvent then rises up the paper taking each component of the sample with it
5. when it reached the end then take it out and air dry it

Question 4

the travelling of the solvent depends on the?

Answer 4

• the polarity of the sample molecule. non-polar ones tend to travel faster
• attraction between sample and solvent

Question 5

what can you interpret from a chromatogram?

Answer 5

a pure substance produces one spot whereas impure produce two or more.

two substances are likely to the same if:

• produce the same number of spots and they match in colour
• spots travel the same distance ( have the same rf value)

Question 6

what is the formula to work out the Rf value?

Answer 6

Rf = distance moved by the compound/ distance moved by the solvent

Question 7

what is adsorbent?

Answer 7

solid substance used to collect solute molecules from a liquid or gas

Question 8

what is elution?

Answer 8

that is the process of removing an absorbed material from an adsorbent

Question 9

what is polar?

Answer 9

a structure having an uneven distribution of electron density

Question 10

what is eluent?

Answer 10

its the carrier of the mobile phase