Transcript Paper Chromatography Lab

Paper Chromatography
Lab
ACP Chemistry
Chromatography
What is
Chromatography?
• “Written in Color”
• Method used to separate mixtures
• Place drop of solution on close to
bottom of filter paper
• Filter paper – stationary phase
• Paper placed in small amount of
solvent – mobile phase
Separation
• When the solvent reaches the
solution the components move with
the solvent, but at a different rate…
why?
• Strong affinity for paper – slow
• Strong affinity for solvent – fast
Seeing Spots
• All components will occupy a certain
spot on the paper.
• They may be visible or after spraying
the paper with substances that react
with them.
Going the Distance
• Solvent front – distance the solvent
traveled
• Retention Factor (RF) – distance
traveled by the spot with respect to
distance traveled by solvent
• RF = Dspot/Dsolvent
• RF should always be less than 1.
RF Value
• The RF value of a substance is
constant and is a characteristic of
that substance.
• RF of 60% ethanol = .66. If the
solvent front traveled 6.5 cm, where
should the spot for ethanol appear?
Your Lab
• You will test four different
compounds: CoCl2, NiCl2, CuCl2, FeCl3
• A mixture of all four
• An unknown mixture using some of
the four knowns.
Safety
• HCl is 6M – can cause burns
• NH3, ammonia, can also cause burns
when it is sprayed.
• Dimethylglyoxime is flammable
• Acetone is very volatile and
flammable
• Wear gloves when spraying