Chromatography

Question 1

Chromatography

Answer 1

Physical separation technique, Measures the rate at which components flow through the stationary phase

Question 2

Stationary phase

Answer 2

What the mixture flows through

Question 3

Mobile phase

Answer 3

Dissolves the components of the mixture

Question 4

ADsorption

Answer 4

Where the components adhere/bond with the stationary phase

Question 5

Desorption

Answer 5

When the components dissolve (bond with) into the mobile phase

Question 6

Paper chromatography stationary phase

Answer 6

piece of paper placed in the solvent

Question 7

Paper chromatography mobile phase

Answer 7

Solvent the paper is placed in

Question 8

What is thin layer chromatography used for

Answer 8

Used to separate and analyse a wide variety of molecular mixtures

Question 9

Thin layer chromatography

Answer 9

Uses a thin layer of silica gel or aluminium oxide coated onto a piece of glass, metal or plastic, faster and provides more separation than paper chromatography

Question 10

Stationary phase in thin layer chromatography

Answer 10

silica gel or aluminium oxide, fine powder on glass or plastic

Question 11

Mobile phase in thin layer chromatography

Answer 11

liquid solvent or mixture such as ethanol or water

Question 12

Speed of particles in thin layer chromatography

Answer 12

Particles most attracted to the stationary phase move the slowest, Particles most strongly attracted to the solvent move the fastest

Question 13

How do you know if samples are the same

Answer 13

If they have the same retardation factor

Question 14

Retardation factor

Answer 14

Value assigned to each component in a sample once the chromatogram is developed, Ratio that expresses how far each component has moved from the origin relative to how far the solvent has moved, taken from distance of starting point to centre of the dot, Distance component travelled from origin/distance solvent from travelled from origin

Question 15

Gas chromatography

Answer 15

Separation technique for small organic molecules that can withstand relatively high temperatures, Consists of a gas bottle, an oven, a column, a detector and a recorder, Separates compounds with a high vapour pressure and low boiling point

Question 16

How does gas chromatography work?

Answer 16

Sample is injected into the oven where the unreactive gas pushes the sample into the long, thin column where smaller particles and those that adsorb onto the stationary phase the least leave the column first

Question 17

Stationary phase is gas chromatography

Answer 17

Long, thin column

Question 18

Mobile phase in gas chromatography

Answer 18

Unreactive gas such as nitrogen or helium

Question 19

what is high performance liquid chromatography used for

Answer 19

Used for larger organic molecules that may be unstable to heat

Question 20

Stationary phase is HPLC

Answer 20

Column (shorter than in gas chromatography)

Question 21

Mobile phase in HPLC

Answer 21

Liquid that has to be pumped such as water-methanol

Question 22

Retention time

Answer 22

Time taken for a particular component to pass through the HPLC or GC column, Stronger interaction = longer compound interacts with the stationary phase = longer retention time, Measured by area under the peak of the component- quantitative amount

Question 23

Calibration curve

Answer 23

Determines concentration of an unknown substance in an unknown sample by comparing the unknown with a known set of standards, Relates to the peaks on chromatograms to the mixture composition