Separating immiscible liquids E Haniff Objectives Separate a mixture of different solutions using a given solvent by difference of solubilities Separate a mixture of immiscible liquids ID: 312666
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Slide1
Paper Chromatography and Separating immiscible liquids
E.
HaniffSlide2
ObjectivesSeparate a mixture of different solutions using a given solvent (by difference of
solubilities
)
Separate a mixture of immiscible liquidsSlide3
What are immiscible liquids?
Immiscible liquids are two liquids which cannot be dissolved in one another
They form two distinct layersSlide4
Separating immiscible liquidsSlide5
Title: Separation of two immiscible liquids
Aim: To separate a mixture of oil and water
Apparatus and materials: Separating funnel with tap, water, oil and 3 containersSlide6
Diagram:Slide7
Method
The apparatus was set up as shown in the diagram
The denser liquid at the bottom of the separating funnel was withdrawn through the tap and collected in a container
The container was then replaced with another and a small quantity of liquid was withdrawn (a mixture of the two right after the denser liquid was withdrawnSlide8
Method continued…
The container was then replaced again and the less dense liquid was allowed to run out and was collected.
Observations were notedSlide9
Observations
Two separate layers were formed in the separating funnel.
The oil was seen at the top layer and the water at the bottom layerSlide10
Discussion
The separation of two immiscible liquids is based on the principle that the two liquids do not mix and form two distinct layers
The less dense liquid was the oil, which formed the top layer
The denser liquid was the water which formed the bottom layer and was withdrawn first, allowing the separation of the two liquidsSlide11
Conclusion
The mixture of oil and water was separated using a separating funnel
Oil and water are immiscible liquids because they do not dissolve one anotherSlide12
Application….
The principle of immiscibility of liquids in some solvents is used in solvent extraction
Solvent extraction is used to separate a component from a mixture by using two solvents.
Two conditions have to be met:
The component must be more soluble in one solvent than in the other
The two solvents must be immiscibleSlide13
For example…
pg
75
To compare the solubility of iodine in two solvents
Iodine is dissolved in water
The water is mixed with 1,1,1-trichloroethane
The iodine goes into this solvent and the water can be drained off in a separating funnelSlide14
Another exampleSlide15
Uses of solvent extraction
Good for removing organic molecules from water
For example caffeine from tea or coffee.
Caffeine is an organic compound which is more soluble in an organic solvent which is immiscible with water.(Dichloromethane)Slide16
Title: Paper Chromatography
Aim: To separate the components of screened methyl orange
Apparatus and materials: filter paper, beaker, capillary tube, test tube, screened methyl orangeSlide17
Diagram:Slide18
Method:
To a strip of filter paper, a capillary tube was used to place a small drop of methyl orange, close to the base of the paper
A small volume of water was placed in a test tube or beaker
The strip of filter paper was suspended so that it barely touched the solventSlide19
Method:
It was left to stand for a while
Observations were recordedSlide20
Observations
The liquid moved up the filter paper
Distinct
colours
could be seen
The
colour
that moved the furthest up the filter paper was…….Slide21
ObservationsSlide22
Discussion
Chromatography is a technique that uses a stationary phase and a mobile phase
The stationary phase is the filter paper in paper chromatography
The mobile phase is the solvent that moves up the paper
Chromatography can be used to separate minute quantities of substances.Slide23
Discussion
Separation of the different components occurs because each substance is soluble to different extents in the chosen solvent (the mobile phase)
The more soluble component travels the furthest up the filter paper and the least soluble remains closer to the base
Two
colours
were seen in screened methyl orange: two dyes a blue and a yellowSlide24
Conclusion
Screened methyl orange contains two components: a blue dye and a yellow dye
The more soluble component appeared blue in
colour
The blue dye was more soluble in waterSlide25
Applications of chromatography
Testing for trace contaminants in the environment
Monitoring water quality and air quality
Analyzing pure samples for trace contaminants (pharmaceutical industry)
Quality control in
food industry