paper chromatography and separating immiscible liquids

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Paper Chromatography and 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. What are immiscible liquids?. - PowerPoint PPT Presentation


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Paper Chromatography and Separating immiscible liquids

E. HaniffObjectivesSeparate a mixture of different solutions using a given solvent (by difference of solubilities)Separate a mixture of immiscible liquidsWhat are immiscible liquids?Immiscible liquids are two liquids which cannot be dissolved in one anotherThey form two distinct layersSeparating immiscible liquids

Title: Separation of two immiscible liquidsAim: To separate a mixture of oil and waterApparatus and materials: Separating funnel with tap, water, oil and 3 containersDiagram:

MethodThe apparatus was set up as shown in the diagramThe denser liquid at the bottom of the separating funnel was withdrawn through the tap and collected in a containerThe container was then replaced with another and a small quantity of liquid was withdrawn (a mixture of the two right after the denser liquid was withdrawnMethod continuedThe container was then replaced again and the less dense liquid was allowed to run out and was collected.

Observations were notedObservationsTwo separate layers were formed in the separating funnel. The oil was seen at the top layer and the water at the bottom layerDiscussionThe separation of two immiscible liquids is based on the principle that the two liquids do not mix and form two distinct layersThe 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liquid was the oil, which formed the top layer The denser liquid was the water which formed the bottom layer and was withdrawn first, allowing the separation of the two liquids

ConclusionThe mixture of oil and water was separated using a separating funnelOil and water are immiscible liquids because they do not dissolve one another

Application.The principle of immiscibility of liquids in some solvents is used in solvent extractionSolvent 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 otherThe two solvents must be immiscible

For examplepg 75To compare the solubility of iodine in two solventsIodine is dissolved in waterThe water is mixed with 1,1,1-trichloroethaneThe iodine goes into this solvent and the water can be drained off in a separating funnel

Another example

Uses of solvent extractionGood for removing organic molecules from waterFor 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)

Title: Paper ChromatographyAim: To separate the components of screened methyl orangeApparatus and materials: filter paper, beaker, capillary tube, test tube, screened methyl orangeDiagram:

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 paperA small volume of water was placed in a test tube or beakerThe strip of filter paper was suspended so that it barely touched the solvent

Method:It was left to stand for a while Observations were recordedObservationsThe liquid moved up the filter paperDistinct colours could be seenThe colour that moved the furthest up the filter paper was.Observations

DiscussionChromatography is a technique that uses a stationary phase and a mobile phaseThe stationary phase is the filter paper in paper chromatographyThe mobile phase is the solvent that moves up the paperChromatography can be used to separate minute quantities of substances.

DiscussionSeparation 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 baseTwo colours were seen in screened methyl orange: two dyes a blue and a yellow

ConclusionScreened methyl orange contains two components: a blue dye and a yellow dyeThe more soluble component appeared blue in colourThe blue dye was more soluble in water

Applications of chromatographyTesting for trace contaminants in the environmentMonitoring water quality and air qualityAnalyzing pure samples for trace contaminants (pharmaceutical industry)Quality control in food industry


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