3.5. Chemical analysis

Chromatography

A technique that separates the components of a substance

Phases of chromatography

Stationary phase (paper/silica)

Mobile phase (solvent/liquid/gas)

How does solubility affect the separation of components?

The more soluble a substance is in the mobile phase the faster it moves up the stationary phase 

How does attraction affect the separation of components?

The more attracted a substance is to the stationary phase the slower it will move up it 

In a polar solvent, what substances will move fastest?

Polar substances (more soluble)

In a non-polar substance, what substances will move fastest?

Non-polar substances (more soluble)

How does molecule size affect its speed in chromatography 

Larger molecules move slower, they are heavier 

Retention factor formula

R_f = spot distance / solvent distance = a / b

Applications of chromatography

Pharmaceuticals, forensics, environmental testing 

In a chromatography graph, what does the area under a peak indicate?

Its concentration