Science class 6 , Ch.5 (Separation of substances) Keywords and Exercise Solution ':- PDF Download

Keywords:

1. Churning - It is a method of separation that is used to obtain butter from curd or milk.

2. Condensation - The changing of water vapour into liquid form on cooling is called condensation.

3. Sedimentation - We take muddy water in a beaker and allow it to settle down at the bottom of the beaker; it's called sedimentation.

4. Decantation - When mud settles down at the bottom of the weaker than we separate clear water it's called decantation.

5. Evaporation - The changing of water into vapour in heating form is called evaporation.

6. Filtration - separating components of a mixture with the help of filter paper.

7. Handpicking is the method of separation in which the components of the mixture are separated by hand.

8. Saturated solution - the solution in which no more salt can be dissolved is called saturated solution.

9. Sieving is the method of separation in which a larger component of a mixture is Separated from a small one with the help of a sieve.

10. Solution - When salt dissolves in liquid, then the mixture is called a solution.

11. Threshing - The method of separation of grain from stock by eating crops called threshing.

12. Winnowing - Separation of grain from husk particles with the help of wind.

Exercise:

Q.1: Why do we need to separate different components of the mixture? Give two examples. 
Ans: We need to separate substances to separate two useful substances from its mixture. Sometimes, we separate waste from useful components. E.g., butter & milk, stones & grain.

Q.2: What is winnowing? Where is it used? 
Ans: Winnowing is a separation method that is used to remove husker particles from grain.

Q.3: How will you separate husk or dirt particles from a given sample of pulses before cooking? 
Ans: We will separate husk or dirt particles from pulses by winnowing.

Q.4: What is Sieving? Where is it used? 
Ans: Sieving is the separation of components of a mixture with the help of a sieve. This method is used to separate tea leaves from tea.

Q.5: How will you separate sand and water from their mixture? 
Ans: We will separate sand and water from their mixture by sedimentation, decantation, and filtration.

Q.6: Is it possible to separate sugar mixed with wheat flour if yes, how will you do it? 
Ans: Yes, it is possible to separate sugar flour by sieving.

Q.7: How would you obtain clear water from a sample of muddy water? 
Ans: We will separate the desperate clear water from muddy water by sedimentation and decantation.

Q.8: Fill in the blanks:- 
1. The method of separating the seeds of paddy from its stalks is called ________. 
Ans: "Threshing"

2. When milk cools after boiling, it is poured onto a piece of cloth cream, which is left behind. This process of separating cream from milk is an example of ________ and ________. 
Ans: Churning & Filtration

3. Salt is obtained from sweaters by the process of _______. 
Ans: Evaporation

4. Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clearwater was then poured off from the top. The process of separation used in this example is called ______ and _______. 
Ans: Decantation and Sedimentation

Q.9: True OR False:- 
1. A of milk and water can be separated by filtration. _______ 
Ans: False

2. A mixture of powdered salt and sugar can be separated by the process of winnowing. _____ 
Ans: False

3. Separation of sugar from tea can be done with filtration. ______ 
Ans: False

4. Grain & husk can be separated with the process of decantation. _______ 
Ans: True

Q.10: Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add eyes to the lemonade before or after dissolving sugar? In which case would it be possible to dissolve more sugar? 
Ans: We will add sugar after dissolving it because, in warm water, more salt can be dissolved in soils.