2The Different Separation Techniques are as follows: Magnetic attractionFiltrationEvaporationCrystallisationDistillationChromatographyNote: The physical methods used will depend on the nature of its constituents.
3Magnetic AttractionThis process is used to separate magnetic materials, e.g. iron, steel, nickel, cobalt from non-magnetic ones in a mixture, e.g. separating iron filings from sulphur powder.
4Applications of Magnetic Attraction 1. Electromagnets are used to remove steel and iron scrap at the junk-yard.2. In hospitals, magnets are often used to remove iron splinters from a patient’s eyes.
5Using a Separating Funnel A separating funnel can be used to separate two immiscible liquids, such as oil and water.
6FiltrationThis process is used to separate insoluble solids from the liquid in a solid-liquid mixture, e.g. separating sand from a mixture of sand and water.The insoluble solid that remains on the filter paper is called residue. The liquid that passes through is called the filtrate.
7Applications of Filtration air filters in air conditionersremove solid impurities from airhair in our nostrilstrap the dust particles that we breathe in and allow only clean air to pass throughoil and air filters in carsremove solid impurities found in engine oil and air
8EvaporationEvaporation is used to separate a dissolved solid that does not decompose on heating from a solution, e.g. common salt from a salt solution
9Evaporating a Solution 1. Pour the solution into an evaporating dish.2. Heat the solution to dryness to evaporate away the solvent, leaving behind the solute.3. Make the Bunsen flame smaller when almost all the solvent has been evaporated away to reduce spitting.
10Applications of Evaporation drying wet clothesdrying hair with a hair-dryerobtaining common salt from the seadrying salted fish or vegetables
11CrystallisationCrystallisation is a process to obtain a solid that decomposes on heating from its solution.Sugar can be obtained from sugar solution and copper(II) sulphate crystals can be obtained from copper(II) sulphate solution by the process of crystallisation
12DistillationDistillation is a process used to separate a liquid(solvent) from a solid-liquid solution or liquid-liquid solution.Pure water can be distilled from a soft drinks
14Fractional Distillation This process can be used to separate miscible liquids with different boiling points where the liquid with the lower boiling point will vaporize firstWe can use this method to separate crude oil into various useful components.
19ChromatographyChromatography is a process used to separate the different components in a liquid or gaseous mixture.For example it can be used1. to separate the different coloured components that make up black ink2.to detect tiny amounts of drugs or certain other chemicals in urine samples
20Paper Chromatography1. Apply a small but concentrated spot of the solution on a piece of chromatography paper.2. Suspend the chromatography paper in a beaker or boiling tube of solvent with the spot above the level of the solvent.
21Paper Chromatography3. Separation takes place because some components of the liquid mixture travel at a faster pace than other components on the paper or any other absorbent material.
22Chromatography3. As the solvent travels up the paper, the mixture is separated into its respective components.A chromatogram of the separated components is obtained.
26Applications The End analysing ink dyes for forgery cases analysing food dyes to ensure that only permitted colourings are used in foodstuffschecking whether pesticides on vegetables exceed safe levelsdetecting trace levels of drugs in urine samplesThe End