Purification Flashcards
(16 cards)
What is purity?
A substance is pure if it’s completely made up of a single compound or element.
How can purity be tested for?
It can be tested fro using melting points. If a substance is pure, the melting point will be specific.
What is distillation used for?
Distillation is used to desperate mixtures that contain liquids.
What two types of distillation will be covered in the exam?
Simple and fractional.
What is simple distillation used for?
It is used for separating a liquid from a solution, for example, extracting pure water from sea water.
Identify a problem with simple distillation.
You can only use simple distillation to separate things with very different boiling points.
What is fractional distillation used for?
It is used to separate a mixture of liquids which may have similar boiling points.
What is filtration used for?
Filtration is used to separate an insoluble solid from a liquid.
What is the method of filtration?
Put filter paper into a funnel and pour the mixture into it. The liquid runs through the paper leaving a solid residue behind.
What is crystallisation used for?
Crystallisation is used to separate a soluble solid from a solution.
What is the method of crystallisation?
1-Pour the solution into an evaporating dish and heat the solution.
2-When it reaches the point
of crystallisation, remove the dish from the heat and leave to cool. (it sounds like i’m making food lmao)
3-The salt should start to from crystals as it becomes insoluble in the cold, highly concentrated solution.
4-Filter the crystals out of the solution and leave them n a warm place to dry.
What is paper chromatography used for?
It is used to separate a mixture of soluble substances and identify them.
What are the two phases in chromatography?
- The mobile phase.
- The stationary phase.
What is the mobile phase of chromatography?
It’s where the molecules can move. This is always a liquid or a gas.
In paper chromatography, what is the mobile phase?
A solvent, for example, ethanol or water.
In paper chromatography, what is the stationary phase?
A piece of filter paper.
