1.4 Fractional distillation and paper chromatography Flashcards
The process of distillation can separate what mixtures?
- Miscible liquids
(ethanol and water)
What does the word miscible mean?
Describes liquids that can dissolve in each other completely.
They will not form separate layers seen in mixtures that are called immiscible.
What are immiscible means?
Immiscible means that liquids that have been allowed to settle such as oil and water layers in a salad dressing.
What will miscible liquids have?
- Different boiling points so you can distil off and collect the liquid with the lowest boiling point first.
Why is it difficult to get pure liquids from a mixture of liquids with similar boiling points by simple distillation?
- Vapour is given off from each liquid before they can actually reach the boiling point.
How would you aid for separation for distillation?
Fractionating column
What does a fractioning column look like?
Tall glass column filled with glass beads fitted vertically on the top of the flash being heated.
What equipment does fractional distillation include?
- Thermometer
- Fractionating column containing glass beads.
- Heat
- Condenser
- Ethanol
What does fractional distillation mean?
The effective way of separating miscible liquids , using fractionating column. The separation is possible because of the different boiling points of the liquids in the mixture.
What is fractional distillation used as an example?
Separate ethanol from the fermented mixture in the alcoholic spirits industry and in the use of ethanol as a biofuel.
What is paper chromatography?
This separates mixtures of substances dissolved in a solvent as they move up a piece of chromatography paper.
Why are different substances separated ?
Different solubilities in the solvent used
What is the process of paper chromatography?
1) First of all capillary tube is used to dab a spot of the solution on a pencil line near the bottom of the sheet of absorbent chromatography paper.
2) The paper is placed standing in the solvent at the bottom of beaker/tank.
3) Solvent soaks up the paper running through the spot of the mixture.
What determines on how far they travel on the paper?
The relative solubility of the components making up the mixture in the solvent.
What does it mean when a substance is more soluble in the solvent?
It goes further up the paper it is carried. Different solvents can be used to maximise the separation.
