chapter 13 - chromatography

Question 1

chromatography

Answer 1

• separate parts of a mixture
• stationary phase
• mobile phase
• moves through the stationary phase by adsorbing to SP and desorbing and dissolving in MP
  very soluble components move quickly
  components that strongly adsorb to SP move slowly

Question 2

stationary phase

Answer 2

does not move
solid/ beads coated in a viscous liquid

Question 3

mobile phase

Answer 3

moves over stationary phase
liquid/ gas

Question 4

process of chromatography

Answer 4

1. sample placed at origin
2. MP is added, sample moves up SP as the MP carried it up
3. different components separate as they adsorb onto SP and desorb back onto MP and dissolve, and continue up

Question 5

Rf

Answer 5

retention factor
Rf of component is compared to Rf value of known substances, under same conditions
Rf = distance component travels from origin / distance solvent travels from origin

Question 6

column chromatography

Answer 6

SP - packed solid
MP - liquid
- separation is better than paper
- larger sample needed
- components can be collected
- top is greatest adsorption/ attraction to SP = longest Rt
- bottom least adsorption to SP/ most attraction to MP = shortest Rt

Question 7

high performance liquid chromatography (HPLC)

Answer 7

SP - very fine particles (non-polar) better separation due to SA
MP - liquid (polar)
- small sample needed

Question 8

chromatogram

Answer 8

• eluted components pass though UV light
• absorbed by components
• gives peaks
• Rt compared to known substances

Question 9

calibration graph

Answer 9

graph known concentrations
y - peak area (mm^2)
x - concentration (mu g mL-1)