Methods of separating and purifying substances

HideShow resource information
Explain the difference between the word 'pure' during everyday use and in scientific terms.
In everyday use the word 'pure' is used to say that there is nothing extra added however scientists say that a pure substance has to be an element or a compound. They have to have the same molecules.
1 of 9
What are the differences between a mixture and a pure substance?
A mixture has two or more elements that are not chemically combined, however a pure substance only has the same elements or the same molecules.
2 of 9
How can you tell whether a metal is pure or impure by looking at a melting point graph?
On a melting point graph if the line is horizontal at the temperature that it melts at then it is a pure substance however if the line is more diagonal and has a range then it is an impure substance.
3 of 9
Explain the method of separating mixtures by simple distillation.
Simple distillation is when water is heated in a flask and the vapour travels along the delivery tube where it condenses. A condenser is also used to keep the tube cool so that almost all of the vapour condenses rather than escapes. PURIFY WATER.
4 of 9
Explain the method of separating mixtures by fractional distillation.
Fractional distillation is when 2 or more liquids are being separated. Some liquids have lower boiling points than others so they turn into vapour first. SEPARATE PRODUCTS IN CRUDE OIL.
5 of 9
Explain the method of separating mixtures by filtration.
Filtration is used to separate an insoluble solid from a liquid. The solution is poured into the filter paper and the liquid passes through whereas the solid doesn't. SAND AND WATER.
6 of 9
Explain the method of separating mixtures by crystallisation
Crystallisation is used to separate a soluble solid from a liquid. The solute can be separated from the solution by evaporating the solvent to leave crystals behind. TABLE SALT
7 of 9
Explain the method of separating mixtures by chromatography.
Chromatography is used to separate substances based on the solubility. A small dot of the substance is added and placed in beaker of solvent. The solvent carries the substance up the paper and it separates into the different colours. CRIME SCENES.
8 of 9
Describe appropriate techniques to use to separate a mixture.
If it is an ink/dye use chromatography. If it has a solid and a liquid use filtration or crystallisation. If it contains 2 soluble liquids use simple distillation. If it contains 3+ then use fractional distillation.
9 of 9

Other cards in this set

Card 2

Front

What are the differences between a mixture and a pure substance?

Back

A mixture has two or more elements that are not chemically combined, however a pure substance only has the same elements or the same molecules.

Card 3

Front

How can you tell whether a metal is pure or impure by looking at a melting point graph?

Back

Preview of the front of card 3

Card 4

Front

Explain the method of separating mixtures by simple distillation.

Back

Preview of the front of card 4

Card 5

Front

Explain the method of separating mixtures by fractional distillation.

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Seperating and purifying substances resources »