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Explains the various separation techniques.
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Text by Mrs TeoVideo clips taken from school video repository
Instructions
1. You have learnt that a mixture is made up of components not chemically combined together.Thus the components can be separated by several methods.2. Go through this lesson package on the various separation techniques.3. Follow up by reading your textbook.
1. A mixture is made up of components not chemically combined together, e.g. ink, fizzy drinks, mineral water, crude oil, air
2. The components of a mixture can be separated by several methods or techniques.
3. Each separation technique makes use of differences in the physical properties of the components
The Different Separation Techniques are as follows:
• Magnetic attraction• Filtration• Evaporation• Crystallisation• Distillation• Chromatography
The Different Separation Techniques are as follows:
• Magnetic attraction• Filtration• Evaporation• Crystallisation• Distillation• Chromatography
•• used used to separate to separate magneticmagneticmaterials,materials, e.g. iron, steel, nickel, e.g. iron, steel, nickel, cobalt cobalt from from nonnon--magneticmagnetic ones in a ones in a mixturemixture
e.g. separating iron filings from e.g. separating iron filings from sulphursulphur powderpowder
Magnetic AttractionMagnetic Attraction
1.1.ElectromagnetsElectromagnets are are used to used to removeremovesteel and iron scrapsteel and iron scrapat the junkat the junk--yard.yard.
Applications of Magnetic AttractionApplications of Magnetic Attraction
2.2. In hospitals, In hospitals, magnetsmagnets are often used are often used to to remove iron splintersremove iron splinters from apatientpatient’’s eyes.s eyes.
Using a Separating FunnelUsing a Separating Funnel
•• can be used to can be used to separate two separate two
immiscible liquidsimmiscible liquids,, such as oilsuch as oil
and waterand water
http://vle.hci.edu.sg/chemistry/beijing/expt%20techniques/lesson5.html
Filtration• used to separate (i) an insoluble solid from a liquid in a solid-liquid
mixturee.g. sand from a mixture of sand and water
(water that passes through filter paper)
sand)
Filtration
• (ii) used to separate an insoluble solid froma soluble solid
e.g. insoluble calcium carbonate fromsoluble copper(II) sulphate
Filtration
• insoluble solid that remains on the
filter paper - residueresidue
• liquid that passes through- filtratefiltrate
(filtrate can be water, any other (filtrate can be water, any other solvent, or a solution)solvent, or a solution)
• hair in our nostrils
trap the dust particles that we breathe in and allow only clean air to pass through
• air filters in air conditioners
remove solid impurities from air
• oil and air filters in cars
remove solid impurities found in engine oil and air
• hair in our nostrils
trap the dust particles that we breathe in trap the dust particles that we breathe in and allow only clean air to pass throughand allow only clean air to pass through
• air filters in air conditioners
remove solid impurities from airremove solid impurities from air
• oil and air filters in cars
remove solid impurities found in engine remove solid impurities found in engine oil and airoil and air
Applications of FiltrationApplications of Filtration
• used to separate a dissolved solid (solute) that does not decompose on heating from a solution,
e.g. common salt from a salt solution
•• used to used to separate a dissolved solid separate a dissolved solid (solute)(solute) that that does notdoes not decomposedecompose on on heating heating from a solution,,
e.g. common salt from a salt solutione.g. common salt from a salt solution
Evaporation to drynessEvaporation to dryness
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.
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.
Procedure of Evaporating a SolutionProcedure of Evaporating a Solution
• drying wet clothes
• drying hair with a hair-dryer
• obtaining common salt from the sea
•• drying wet clothes drying wet clothes
•• drying hair with a hairdrying hair with a hair--dryerdryer
• obtaining common salt from the seaobtaining common salt from the sea
Applications of Evaporation
• process to obtain a solid thatdecomposes on heating from its solution
e.g. sugar crystals from sugar solution and copper(II) sulfatecrystals from copper(II) sulfate solution
•• process to obtain a solid thatdecomposes on heating from its solution
e.g. sugar crystals from sugar solution and copper(II) sulfatecrystals from copper(II) sulfate solution
Crystallisation
Procedure of Crystallisation
1. Pour the solution, e.g. copper (II) sulfate solution, into an evaporating dish.
2. Heat the solution to evaporate away the solvent until some solid starts to appear or a saturated solution is obtained.
3. Leave the solution to cool.4. On cooling crystals of the solute that can no
longer disssolve in the solution will be deposited as crystals.
5. Filter the mixture to collect the crystals which will be the residue.
• process used to separate a pure liquid(solvent) from a solid-liquid solution
e.g. pure water can be distilled from soft drinks, sea-water, etc
•• process used to separate a pure liquid(solvent) from a solid-liquid solution
e.g. pure water can be distilled from soft drinks, sea-water, etc
Simple DistillationSimple Distillation
Distillation
Simple DistillationSimple Distillation
• solution boiled in distilling flask and vapour/steam cooled and condensed in a Liebig condenser
• condenser consists of jacket of cold water with coldest water entering bottom of jacket and circulating out through the top ensuring that coldest part of condenser is just before the vapour escapes and that the jacket is completing full of water
• condensed solvent – distillate• all impurities left in distilling flask• anti-bumping granules/boiling chips/beads-ensure even
boiling
• process can be used to separate miscible liquids with different boiling points
• liquid with lower boiling point will vaporise first
e.g. to separate alcohol and water
• process can be used to separate miscible liquids with different boiling points
• liquid with lower boiling point will vaporise first
e.g. to separate alcohol and water
Fractional DistillationFractional Distillation
Fractional Distillation
• oil refineries- separating the various components of
crude oil or petroleum
Industrial Applications of Fractional Distillation
• industries supplying oxygen to hospitals,shipyards, etc
– separating the components of air
Industrial Applications of Fractional Distillation
1. to separate the different colouredcomponents that make up black ink2. to detect tiny amounts of drugs or certain other chemicals in urine samples
1. to separate the different 1. to separate the different colouredcolouredcomponentscomponents that make up that make up black inkblack ink
2. to detect 2. to detect tiny amounts of drugstiny amounts of drugs or or certain other chemicals in certain other chemicals in urine samples
Paper Chromatography
• process used to separate the different components in a liquid mixture
For example it can be usedFor example it can be used
1. Apply a small but concentratedspot of the solution on a piece of chromatography paper.2. Suspend the chromatographypaper in a beaker or boiling tube of solvent with the spot above the level of the solvent.
1. Apply a small but concentrated1. Apply a small but concentratedspot of the solution on a piece of spot of the solution on a piece of chromatography paper.chromatography paper.2. Suspend the chromatography2. Suspend the chromatographypaper in a beaker or boiling tube of paper in a beaker or boiling tube of solvent with the spot above the solvent with the spot above the level of the solvent.level of the solvent.
Paper ChromatographyPaper Chromatography
Paper Chromatography
3. 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.
Paper ChromatographyPaper Chromatography
3. 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.
Paper Chromatography
3. As the solvent travels up the paper, the mixture is separated into its respective components.
A chromatogram of the separated components is obtained.
Paper ChromatographyPaper Chromatography
3. As the solvent travels up the paper, the mixture is separated into its respective components.
A chromatogram of the separated components is obtained.
YouTube video clip
Applications
•analysing ink dyes for forgery cases
•analysing food dyes to ensure that only permitted colourings are used in foodstuffs
•checking whether pesticides on vegetables exceed safe levels
•detecting trace levels of drugs in urine samples
Applications
••analysinganalysing ink dyes for forgery casesink dyes for forgery cases
••analysinganalysing food dyes to ensure that food dyes to ensure that only permitted only permitted colouringscolourings are used are used in foodstuffsin foodstuffs
•checking whether pesticides on vegetables exceed safe levels
••detecting trace levels of drugs in detecting trace levels of drugs in urine samples urine samples
Sublimation- process by which a substance changes from solid
state to vapour state on heating- e.g of substances which sublime
- iodine- ammonium chloride
On heating, they do not melt. Iodine changesinto a beautiful violet vapour while ammoniumchloride changes into a white vapour.They change back into solid crystals on cooling.
- process used to separate a solid that sublimes from one that does note.g. iodine or ammonium chloride from common salt
Sublimation
When a mixture of a solid that sublimesand a solid that does not is heated, thesolid that sublimes will turn into a vapourand separates from the other solid which remains in the container.
Sublimation
The End
ACE Suggestions1. Production of whisky by distillation of barley mash
ACE Suggestions2. Commercial Production of sodium chloride by:
(i) Mining
(ii) Evaporation of sea water