chromatography

Question 1

what is chromatogrpahy

Answer 1

analytical techniques for separating components in a mixture between a mobile and stationary phase.

Question 2

what are the 2 elements of chromatography and explain them?

Answer 2

mobile phase - movement of mixtures at varying speeds based on their solubility.
stationary phase - a solid or liquid that does not move with the mobile phase

Question 3

how are the components of the mixture separated?

Answer 3

the mobile phase moves mixture components at varying speeds based on their solubility.
the stationary phase holds onto the components through adsorption.

Question 4

what are the 4 types of chromatography?

Answer 4

thin layer chromatography
column chromatography
gas chromatography
gas chromatography-mass spectrometry

Question 5

explain each type of chromatography

Answer 5

TLC - a plate is coated with a solid and a solvent moves up the plate
CC - a column is packed with a solid and a solvent moves down the column
GC - a 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 a high temp
GC-MS, used to analyse components separated by GC

Question 6

what is the Rf value and the equation for it?

Answer 6

Rf = the ratio of the distance travelled by a component from the baseline to the distance travelled by the solvent
Rf = distance travelled by spot / distance travelled by solvent

Question 7

measures in place for a valid chromatogram

Answer 7

using a pencil for lines - will not dissolve in the solvent
small drops - large drops will merge together
depth of solvent - if the solvent is too deep, it will dissolve the sample spots
lids - prevent evaporation of toxic solvents

Question 8

when is gas chromatography

Answer 8

used to separate mixtures of volatile liquids