EXERCISE 4

Question 1

What phenomena is affected by the affinity of components of a given mixture between a stationary and mobile phase?

Answer 1

Separation

Question 2

This type of chromatography uses a solid stationary phase and a liquid mobile phase where the transfer of compound between stationary and mobile is at equilibrium.

Answer 2

Adsorption Chromatography

Question 3

The strength of adsorption depends on what?

Answer 3

Polarity. The more polar, the stronger.

Question 4

The separation of components in a mixture depends on what?

Answer 4

The relative values of the adsorption-desorption equilibrium constant (K) for each component.

Question 5

This type of chromatography uses a liquid stationary phase supported by a solid surface and a liquid/gas mobile phase insoluble in the stationary phase.

Answer 5

Partition Chromatography

Question 6

Why do partition chromatographic separations occur?

Answer 6

Becaue of differences in solubility of the sample in stationary and mobile phases.

Question 7

Type of chromatography useful in monitoring reactions, detecting intermediates, analyzing crude products or unknown mixtures, determining the number of components in a mixture, and evaluating efficiency of purification processes.

Answer 7

Thin-layer chromatography

Question 8

Adsorbents used in TLC.

Answer 8

Alumina/Silica Gel

Question 9

Stationary phases used in TLC.

Answer 9

Glass/Aluminum

Question 10

What is filter paper made of?

Answer 10

Highly purified cellulose (polyhydroxy compound)

Question 11

Which phases are polar and nonpolar in the separation that occurs in paper chromatography?

Answer 11

Polar stationary phase and nonpolar mobile phase.

Question 12

Formula for retention factor or Rf.

Answer 12

Distance travelled by compound from origin / Distance travelled by solvent from origin

Question 13

Objectives

Answer 13

1. Learn the techniques of paper and thin-layer chromatography.
2. Apply chromatographic methods in the separation of components of mixtures.
3. Identify an unknown sample by comparing its Rf value and other characteristics with those of a standard.

Question 14

Type of chromatography with nonpolar mobile phase and polar stationary phase.

Answer 14

Normal Phase Chromatography

Question 15

Type of chromatography with a polar mobile phase and nonpolar stationary phase.

Answer 15

Reverse Phase Chromatography

Question 16

Visualizing agent in TLC.

Answer 16

Iodine