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Mixtures and Separating Mixtures. Mixtures. Many of the ordinary things around us are mixtures of a number of different substances. A mixture is made of two or more different substances mingled with each other but not chemically combined.
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Mixtures • Many of the ordinary things around us are mixtures of a number of different substances. A mixture is made of two or more different substances mingled with each other but not chemically combined.
sea water: a mixture of salts and water • Sea water is a mixture of water, salt, and a number of other substances. • Crude oil is one of the most valuable mixtures ever discovered!
When substances are separated from mixtures they are said to be purified • The method of separation depends on the type of mixture.
Filtration is a method of separating an insoluble solid from a liquid
FILTRATION - Choose the sieve!! Each hole is 2.5 mm wide Each hole is 10 mm wide Each particle in the water is 3mm in diameter
FILTRATION Filter funnel with 2.5 mm sieve Well done the sieve size is smaller than the particles so only the water gets through! Conical Flask Start
FILTRATION Filter funnel with 10 mm sieve Nope! the sieve size is larger than the particles so both the water and particles get through! Conical Flask Start
Separating Mixtures Filtration Everyday examples of filtration: • A coffee filter is a piece of paper that separates the coffee solution from the coffee grounds. • An extractor fan above a hob oven removes fumes and smells from the cooking area.
Check your learning.. • What is a mixture? • Why is the sieve size important for filtration? • What does insoluble mean? • Give two examples of mixtures that can be separated by filtration. • What is the filtrate? • What is the residue?
Mixtures and Separating Mixtures Separation Techniques -Evaporation
Sometimes mixtures can be separated by using evaporation… Evaporation is used to separate a soluble solid from a liquid. Separation Techniques -Evaporation
EVAPORATION Time 100oC Particles in water 70oC Water heats up Water begins to evaporate 20oC Water continues evaporating All water evaporated – particles remain Start Separation Techniques -Evaporation
Set up your apparatus like this: Separation Techniques -Evaporation
Evaporation is used to separate sodium chloride from a mixture of sodium chloride in water. When the mixture of sodium chloride and water is heated the water particles turn from a liquid to a gas and then escape from the beaker The sodium chloride is left behind in the evaporating dish Separation Techniques -Evaporation
This can come in very useful! In desalination plants fresh water can be made from salty sea water by using evaporation! A desalination plant in Australia Separation Techniques -Evaporation
Check your learning.. • What is a mixture? • What does soluble mean? • How does evaporation work? • What is the disadvantage of separating a mixture by evaporation?
Mixtures and Separating Mixtures Separating techniques - Chromatography
Chromatography • Chromatography is a way to separate mixtures like a mixture of dyes in ink. Separating techniques - Chromatography
What happens to the ink?? Separating techniques - Chromatography
CHROMATOGRAPHY Take a piece of filter paper Add the coloured ink in small blobs Here Here Here 1 2 3 Draw a Pencil Line Separating techniques - Chromatography
CHROMATOGRAPHY Beaker with a little water Water moves up the paper and so do the inks Now leave for about 15 minutes 2 2 2 2 1 2 1 1 2 3 1 2 3 Start Separating techniques - Chromatography
Which person do you think did the graffiti on the wall? Ink from graffiti Ink from suspect A Ink from Suspect B Ink from suspect C Separating techniques - Chromatography
Learning check.. • Give an example of a type of mixture separated by Chromatography? • How does chromatography work? • What would happen if a mixture was made up of just one colour?
Distillation is used to separate a mixture of a liquid and a soluble solid when the liquid is needed Can you explain what is happening in this experiment?
DISTILLATION Cold water out! 100oC 70oC 20oC Cold water in! Start
What happens to the alcohol when it reaches 78 OC? What happens to the water when it reaches 78 OC? Distillation is used to separate a mixture of liquids when the liquids have different boiling points!