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Thursday, July 19, 2012

Class–IX CHEMISTRY Chapter-2:IS MATTER AROUND US PURE

Separating the Components of a Mixture
Importance of separation--> To study and to use the individual components of a mixture
Q. What would happen if you were to take a saturated solution at a certain temperature and cool it slowly. 
Ans. Different substances in a given solvent have different solubilities at the same temperature. So on cooling substances start to precipitate out.
Q. What is suspension?Write its properties?
Ans: Suspension:Non-homogeneous systems, in which solids are dispersed in liquids, are called Suspensions so It is a heterogeneous mixture.
Properties of a Suspension---
• Suspension is a heterogeneous mixture.
• The particles of a suspension can be seen by the naked eye.
• The particles of a suspension scatter a beam of light passing through it and make its path visible.
• The solute particles settle down when a suspension is left undisturbed, that is, a suspension is unstable.
* They can be separated from the mixture by the process of filtration.
Q. How can we separate colour component of from ink(mixture.)?
Ans: By evaporation method: Water (Solvent) has got evaporated and residue color left over.
Conclusion: we can separate the volatile component (solvent) from its non-volatile solute by the method of evaporation.
Q. How can we separate cream(fat)  from milk ?
Ans: The denser particles of water are forced to the bottom and the lighter particles of cream/fats stay at the top when milk spun rapidly by centrifuge machine.
Centrifugation: Applications-
• Used in diagnostic laboratories for blood and urine tests.
• Used in dairies and home to separate butter from cream.
• Used in washing machines to squeeze out water from wet clothes
Q. How can we separate kerosene oil from water?
Ans: By using a separating funnel.
The principle is that immiscible liquids separate out in layers depending on their densities.
Applications 
• To separate mixture of oil and water.
• In the extraction of iron from its ore, the lighter slag is removed from the top by this method to leave the molten iron at the bottom in the furnace.
Q. How can we separate mixture of salt and ammonium chloride?
Ans: By sublimation method sice ammonium chloride is a sublimating substance
Q. How can we separate dye in black ink?
Ans: Dye in black ink is a mixture of different compounds.
These different compounds can be separated by chromatography method.
The process of separation of components of a mixture is known as chromatography.
Kroma in Greek means colour. This technique was first used for separation of colours, so this name was given.
Chromatography is the technique used for separation of those solutes that dissolve in the same solvent.
Applications: To separate
• colours in a dye • pigments from natural colours • drugs from blood.
Q. What according to you, can be the reason for the rise of the coloured spot on the paper strip?
Ans. The ink that we use has water as the solvent and the dye is soluble in it. As the water rises on the filter paper it takes along with it the dye particles. Usually, a dye is a mixture of two or more colours. The coloured component that is more soluble in water, rises faster and in this way the colours get separated
Further study search related
Jsunil's Chemistry for Class IX - is matter around us pure solved questions 
How to separate,
i) Sulphur from a mixture of sulphur and sand. 
ii) Black CuO from a mixture of CuO and ZnO.
iii) mixture of NH4Cl and I2 iv)the constituents of gunpowder
v) a mixture of ammonia and hydrogen

          Is Matter around Us Pure
CBSE chapter-wise MCQ Multiple Choice Questions, Test Paper, Sample paper   based on CCE pattern for class 9 science Is Matter around Us Pure. Elements, compounds and mixtures. Heterogeneous and homogenous mixtures, colloids and suspensions.

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