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Sunday, May 13, 2012

CBSE 6th Science : Separation of Substances solution


Q. What is solution?
Ans: A solution is a mixture of two or more substance  so that properties are the same throughout . The substance in large quantity is called solvent and The substance in small quantity is called solute.
Q. What is saturated solution?
Ans: if solvent cannot dissolve more solute at room temperature is called saturated solution. A solution is said to be unsaturated as long as more solute can be dissolved.
Q6. State the method used for separating following mixtures:
a) Separating iron from sulphur              magnetic separation
b) Separating oil from water                   decantation
c) Chalk from water                               filtration
d) Bran from flour                                  sieving
e) Pulses from rice                                hand picking
Q. How fat separated from milk?
Ans: Centrifugation or churning method. The method separation involving high speed is called churning using centrifuge machine.
Q. Name process of separating husk from grain?                                                           
Ans: winnowing
Q. How can you turn water vapour into water                                                       
Ans: On cooling called condensation.
Q. what is condition in which no more solute can dissolve in the solvent?                        
Ans: Saturated Solution
Q. What is the left over material known as?                                                         
Ans : Residue
Q. By which process you get flour from husk?                                                   
Ans: Sieving
Q. How do you clean grain at home ?                                                                 
Ans: Hand picking and Sieving
Q. name the part of plant in which grains are embedded ?                                
Ans: Cob
Q. What is the method in which heavier particle allow to settle down?            
 Ans: sedimentation
Q. How are stone and pebble are separated on construction site?                 
Ans : by using sieve called Sieving
Q. How do you carry out churning?                                                                    
Ans: By rotating solution rapidly.
Q. How Chaff or husk is separated from grain after harvesting?              
Ans: It is separated by threshing using thresher.
Q. Explain the method of obtaining common salt from sea water.
Ans. Sea water is collected in shallow pits dug on the sea shore. The heat of sun evaporates water. When enough water has evaporated the solution becomes concentrated, then the salt begins to crystallize.
Q. what is thresher and why it is called an efficient machine  ?
Ans: thresher is a machine that separate husk from grain. It can remove husk ,dusk and produce neat and clean food grain so it is called an efficient machine  .
Q.Fill up the blanks :
(1) The method of separating seeds of paddy from its stalks is called ................... .
(2) When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of ................... .
(3) Salt is obtained from sea water by the process of ................... . 
(4) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off from the top. The process of separation used in this example is called ....................

Ans. (1) The method of separating seeds of paddy from its stalks is called threshing.

(2) When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of filtration.
(3) Salt is obtained from sea water by the process of evaporation .
(4) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off from the top. The process of separation used in this example is called decantation.

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