Separation Techniques
1) The purity of a substance can be determined by measuring its measuring point or its boiling point.
2) A pure solid melts completely at a fixed temperature.
3) A pure liquid boils at a fixed temperature.
4) Impurities lower the melting point of a solid and increase the boiling point of a liquid.
5) When pressure increases, the boiling point of a liquid increases. When pressure decreases, the boiling point of a liquid decreases.
6) Chromatography is used to separate or analyse the components in a sample.
7) Chromatography is also used to determine the purity of a sample. A pure sample gives only one spot on a chromatogram.
8) Rf value = distance travelled by the substance / distance travelled by solvent
9) A locating agent is used on a chromatogram to help us see colourless substances.
10) To determine the purity of a substance, we can:
- check its melting point or boiling point
- perform chromatography
11) Decanting is used to separate a dense, insoluble solid from a liquid.
12) Filtration is used to separate a mixture of a solid and a liquid.
13) Upon filtration, the solid that remains on the filter paper is called the residue. The liquid that passes through the filter paper is called the filtrate.
14) Substances that do not decompose on strong heating can be purified by evaporation to dryness.
15) Crystallisation is used to purify crystals and substances that decompose on strong heating.
16) A saturated solution can be produced by evaporation.
17) Filtration can be used to separate to solids if only one of them is soluble in a solvent.
18) A magnet can be used to separate magnetic substances, such as iron or steel, from non-magnetic ones.
19) Sublimation is used to separate a substance hat sublimes (e.g. iodine) from one with a high melting point (e.g. sand).
(Refer to Manual Journal for more details and pictures of the set-ups)
2) A pure solid melts completely at a fixed temperature.
3) A pure liquid boils at a fixed temperature.
4) Impurities lower the melting point of a solid and increase the boiling point of a liquid.
5) When pressure increases, the boiling point of a liquid increases. When pressure decreases, the boiling point of a liquid decreases.
6) Chromatography is used to separate or analyse the components in a sample.
7) Chromatography is also used to determine the purity of a sample. A pure sample gives only one spot on a chromatogram.
8) Rf value = distance travelled by the substance / distance travelled by solvent
9) A locating agent is used on a chromatogram to help us see colourless substances.
10) To determine the purity of a substance, we can:
- check its melting point or boiling point
- perform chromatography
11) Decanting is used to separate a dense, insoluble solid from a liquid.
12) Filtration is used to separate a mixture of a solid and a liquid.
13) Upon filtration, the solid that remains on the filter paper is called the residue. The liquid that passes through the filter paper is called the filtrate.
14) Substances that do not decompose on strong heating can be purified by evaporation to dryness.
15) Crystallisation is used to purify crystals and substances that decompose on strong heating.
16) A saturated solution can be produced by evaporation.
17) Filtration can be used to separate to solids if only one of them is soluble in a solvent.
18) A magnet can be used to separate magnetic substances, such as iron or steel, from non-magnetic ones.
19) Sublimation is used to separate a substance hat sublimes (e.g. iodine) from one with a high melting point (e.g. sand).
(Refer to Manual Journal for more details and pictures of the set-ups)