chromotagraphy

Question 1

what is chromatography?

Answer 1

analytical techique that separates components in a mixture between a mobile phase and a stationary phase

Question 2

types of chromatography

Answer 2

thin-layer, column, gas

Question 3

thin-layer chromatography

Answer 3

a plate is coated with a solid and a solvent moves up the plate

Question 4

column chromatography

Answer 4

column is packed with a solid and a solvent moves down the column

Question 5

gas chromatography

Answer 5

column is packed with a solid or with a solid coated by a liquid and a gas is passed through the column under pressure at high temperature

Question 6

mobile phase

Answer 6

liquid or gas

Question 7

stationary phase

Answer 7

a solid or either a liquid or solid on a solid support

Question 8

what is used to identify different substances

Answer 8

retention times and rf values

Question 9

method of thin-layer chromatography

Answer 9

) Wearing gloves, draw a pencil line 1 cm above the bottom of a TLC plate and mark spots for each sample, equally spaced along line.
b) Use a capillary tube to add a tiny drop of each solution to a different spot and allow the plate to air dry.
c) Add solvent to a chamber or large beaker with a lid so that is no more than 1cm in depth
d) Place the TLC plate into the chamber, making sure that the level of the solvent is below the pencil line. Replace the lid to get a tight seal.
e) When the level of the solvent reaches about 1 cm from the top of the plate, remove the plate and mark the solvent level with a pencil. Allow the plate to dry in the fume cupboard.
f) Place the plate under a UV lamp in order to see the spots. Draw around them lightly in pencil.
g) Calculate the Rf values of the observed spots

Question 10

what is used if the spots are colourless and not visible?

Answer 10

uv lamp

Question 11

rf value

Answer 11

distance moved by amino acid /distance moved by the solvent

Question 12

method of column chromatography