Sunday, August 5, 2012

Chemistry :Separation of Mixture:Is matter around us pure

Separation of coloured components (due) from blue black ink:
The process of evaporation is suitable for the separation of non-volatile soluble solid (dye) from its liquid solvent (water).
We Pour about 5 cc of the ink into the china dish and Place a china dish on the sand bath. In a few minutes the water evaporates leaving behind dry blue black ink.
Evaporation process is applicable to separate mixture :
1)     Common salt and water
2)     Sodium nitrate and water
3)     Copper sulphate and water
Centrifugation (a very fine suspension or a colloidal solution)
By spinning  the liquid at a very high speed the heavier particles are forced towards the bottom of liquid and the lighter stay at the top.
Applications of centrifugation:
1)     It is employed in milk dairies to separate cream from the milk.
2)     It is employed in diagnostic laboratories in testing urine samples.
3)     It is employed in blood banks to separate different constituents of blood.
4)     It is used in drying machines to squeeze out water from the wet clothes.
Separation of mixture of two immiscible liquids By using Separating Funnel if there is the difference in densities
We allow the mixture to stand for half an hour or more in Separating Funnel. Place a conical flask or a beaker under the nozzle of the separating funnel and turn the tap gently so that the water trickles in the flask or the beaker drop by drop. Once the water is drained out, close the tap.
1)     Benzene from Benzene and water
2)     Kerosene oil from Kerosene oil and water
3)     Water from Chloroform and water
4)     stag (a waste material) form the molten metals during their extraction.
This method is used in the separation of such solid-solid mixtures where one of the components sublimes on heating only if the components of the mixture do not react chemically on heating.
The changing of slid directly into vapours on heating and of vapours into directly solid on cooling is known as sublimation.
Solid-Solid Mixture
Sublimable Solid
Common salt and ammonium chloride
Ammonium chloride                                     
Sand and iodine
Common salt and iodine
Sodium sulphate and benzoic acid
Benzoic acid
Iron fillings and naphthalene
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CCE :IX Chapter: Is matter around us pure : MCQ’S
CCE :IX Chapter: Is matter around us pure : MCQ’S
CCE :IX Chapter: Is matter around us pure : MCQ’S
Fill in the blanks: IX:   Is matter around us pure  
Test yourself: IX :Is matter around us pure :MCQ’S

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