Experiment#5: Chromatography

Question 1

Used to separate mixtures of compounds and identify an unknown.

Answer 1

Chromatography

Question 2

Exploits the differences in solubility and adsorption

Answer 2

Chromatography

Question 3

CHROMATOGRAPHY
A name/name of the phase for the porous material used in chromatography.

Answer 3

Adsorbent or Stationary Phase

Question 4

CHROMATOGRAPHY
A name/name of the phase for the solvent that moves the mixture through the adsorbent.

Answer 4

Eluent or Mobile Phase

Question 5

CHROMATOGRAPHY
Uses a solid stationary phase and a liquid mobile phase, wherein separation is governed by the surface adsorption phenomena.

Answer 5

Adsorption Chromatography

Question 6

Refers to the ability of a substance to “stick” to a surface.

Answer 6

Adsorption

Question 7

ADSORPTION CHROMATOGRAPHY
Molecules of interest which are getting adsorbed on the adsorbent.

Answer 7

Adsorbate

Question 8

ADSORPTION CHROMATOGRAPHY
The extent of adsorption of a single component depends on which 3 factors?

Answer 8

• Polarity of the Molecule
• Activity of the Adsorbent
• Polarity of the Liquid Mobile Phase

Question 9

CHROMATOGRAPHY
Uses a liquid stationary phase supported on the surface of a solid and a liquid or gas mobile phase which is insoluble in the stationary phase.

Answer 9

Partition Chromatography

Question 10

CHROMATOGRAPHY
This type of chromatography is governed by differences in the solubility of the sample in the stationary and mobile phase.

Answer 10

Partition Chromatography

Question 11

PARTITION CHROMATOGRAPHY
Separation is based on _______ ________ between two liquid phases.

Answer 11

Solute Partitioning

Question 12

CHROMATOGRAPHY
A type of solid-liquid adsorption chromatography that uses a thin layer of adsorbent supported on a flat surface as the solid phase.

Answer 12

Thin Layer Chromatography

Question 13

THIN LAYER CHROMATOGRAPHY
What are the 2 possible adsorbents found on the flat surface of a piece of glass or paper used as the solid/stationary phase?

Answer 13

• Alumina
• Silica Gel

Question 14

THIN LAYER CHROMATOGRAPHY
A polar adsorbent that can hydrogen bond.

Answer 14

Silica Gel

Question 15

TRUE or FALSE | THIN LAYER CHROMATOGRAPHY
Polar components of the mixture will interact less with the silica gel and move faster up the TLC Plate.

Answer 15

FALSE. Polar components will interact more, and move less quickly.

Question 16

TRUE or FALSE | THIN LAYER CHROMATOGRAPHY
Non-polar compounds will move faster and migrate further up the TLC Plate.

Answer 16

TRUE

Question 17

THIN LAYER CHROMATOGRAPHY
Provide at least 3 (or all) of the 5 purposes of Thin Layer Chromatography.

Answer 17

• Identify compounds/unknown mixtures
• Detect intermediates in reactions
• Determine the progress of a reaction
• Determine the number of components in a mixture
• Evaluate the efficiency of purification processes

Question 18

CHROMATOGRAPHY
Technique for separating dissolved chemical substances by taking advantage of their different rates of migration across sheets of paper.

Answer 18

Paper Chromatography

Question 19

CHROMATOGRAPHY
Used to separate and identify amino acids in a mixture.

Answer 19

Paper Chromatography

Question 20

PAPER CHROMATOGRAPHY
Made of highly purified cellulose that absorbs and retains water (hydrophilic), serving as the stationary phase.

Answer 20

Filter Paper

Question 21

PAPER CHROMATOGRAPHY
What is the solvent system for Paper Chromatography?

(Hint: 1:2 (v/v) 2% ______ _______-______ _______)

Answer 21

1:2 (v/v) 2% ammonium hydroxide-isopropyl alcohol

Question 22

PAPER CHROMATOGRAPHY
The hydrophic organic solvent is drawn up the paper by ….?

Answer 22

Capillary Action

Question 23

PAPER CHROMATOGRAPHY
A point where the sample is initially spotted on the paper.

Answer 23

Baseline or Origin

Question 24

PAPER CHROMATOGRAPHY
The distance moved by the solvent along the paper.

Answer 24

Solvent Front

Question 25

**COMPLETE THE STATEMENT | PAPER CHROMATOGRAPHY** Separation takes place due to the A) _______ ______ of the components of the mixture for the B) ____ stationary phase and the mobile phase which is a relatively C)_____ solvent or solvent system.

Answer 25

A) Different affinities B) Polar stationary phase C) Non-polar solvent

Question 26

**PAPER CHROMATOGRAPHY** The rate at which the amino acid moves up the paper is related to its _____ ______ for the paper (which is hydrophilic) and the solvent (which is hydrophobic).

Answer 26

Relative Affinity

Question 27

**TRUE or FALSE | PAPER CHROMATOGRAPHY** Amino acids that are more soluble in the ***solvent*** will **move less** on the paper.

Answer 27

**FALSE**. They will **move higher**.

Question 28

**TRUE or FALSE | PAPER CHROMATOGRAPHY** Amino acids that are **more attracted to the paper** will **move higher** on the paper because they wish to cover more ground.

Answer 28

**FALSE**. They **remain closer to the origin line**.

Question 29

**PAPER CHROMATOGRAPHY** Once the chromatogram has dried, the amino acids can be visualized by contacging the dried chromatogram with a 2% ______ solution in acetone.

Answer 29

Ninhydrin

Question 30

A substance that separates and moves constituents of a mixture through the column of a chromatograph.

Answer 30

Eluent

Question 31

Building blocks of proteins.

Answer 31

Amino Acids

Question 32

**AMINO ACIDS** What are the **3 groups** attached to an amino acid’s **central carbon**?

Answer 32

1. Carboxylic Acid Group 2. Amino Group 3. R Group

Question 33

**[AFTER THE EXPERIMENT]** What would be the effect of this following error? - The solvent in the developing chamber is higher than the spotted sample.

Answer 33

The spots will dissolve away

Question 34

**[AFTER THE EXPERIMENT]** What would be the effect of this following error? - Too much sample is applied to the paper.

Answer 34

Deteriorates the quality of the separation (“tailing” occurs).

Question 35

**[AFTER THE EXPERIMENT]** What would be the effect of this following error? - The paper is allowed to remain in the chamber after the solvent front has reached the top of the plate.

Answer 35

Solvent and sample would continue to move up and will all merge together at the top, eliminating any separation that happened earlier.

Question 36

**[AFTER THE EXPERIMENT]** Why is it necessary to cover the developing chamber tightly during the development of a chromatogram?

Answer 36

- Solvent vapor can saturate the air in the chamber to ensure maximum resolution between components. - To prevent the solvent from evaporating.

Question 37

What is the recommended size for samples during spotting?

Answer 37

1-2 Milimeters