Chromotography Flashcards
What is paper chromotography used for ?
Separating the different dyes in an ink
What is the method ?
- Draw a line across the bottom of a piece of filter paper in pencil
- Add sample of ink
- Fill a beaker with a shallow amount of solvent such as water or ethanol
- Place the piece of paper in the solvent without submerging the line or ink
- Lid on top to stop Lovett from evaporating and holds the paper in place
- Leave solvent to seep up the paper to reveal the dyes (basically separating the different substances)
- Once done take out and leave to dry
If any of the chemicals are notsoluble they won’t be able to what?
Dissolve and move up the paper meaning they stay on the baseline
What is the mobile phase ?
Substance that the molecules can move in either a liquid or a gas
Here it’s the solvent
What is the stationary phase
Substance or material that the molecules cannot move in
Here it is the paper
How do we work out the RF value ?
Distances travelled by the substance
Over
Distance traveled by the solvent
If the substances has travelled 6cm but the solvent has travelled 10cm up the page then it’s 6/10= 0.6
What could affect the RF value and how far a substance has travelled ?
Changing the solvent used
Different type of paper
Meaning the RF value would change
We have changed the mobile and/or the stationary phase
What type of process is paper chromatography ?
A physical process
Due to the type of process that paper chromatography is what does this mean ?
Does not involve a chemical reaction
What does paper chromatography allow us to do ?
Separate substances based on their solubilities
What is a solvent ?
A liquid that will dissolve substances
Why is the line drawn in pencil
If it was draw in pen the pen ink could dissolve in the solvent
If a substances is more soluble, what phase would it spend more time in
The mobile phase ( the solvent) so it will travel further than a less soluble substance
What will a pure compound produce ?
A single spot in all solvents
