5. SEPARATION OF SUBSTANCES Science class 6 in English Medium ncert book solutions Exercise (NCERT Text Book)

Exercise (NCERT Text Book)

Q1: Why do we need to separate different components of a mixture? Give two examples.

Ans: A mixture has many impurities and unwanted substances like stone, husk and other materials. These unwanted materials only can be removed by separating methods.

Ex : husk from grains and water from salt.

Q2: What is winnowing? Where is it used?

Ans: Winnowing is a method of separation. It is used to separate heavier and lighter components of a mixture by wind or by blowing air.

Q3: How will you separate husk or dirt particles from a given sample of pulses before cooking?

Ans: By using Sieving Method.

Q4: What is sieving? Where is it used?

Ans: Sieving is method of separating in which a sieve  is used to separate the components of mixture. It is used when components of a mixture have different sizes.

Q5: How will you separate sand and water from their mixture?

Ans: By using the sedimentation and decantation methods.

Q6: Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?

Ans: Yes It can be separated by using sieving method these can be easily separated.

Q7: How would you obtain clear water from a sample of muddy water?

Ans: By using the sedimentation and decantation methods.

Q8: Fill up the blanks: 

(a) The method of separating seeds of paddy from its stalks is called ___________.

(b) 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 ___________.

(c) Salt is obtained from seawater by the process of ___________.

(d) 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. Threshing
2. Centrifugation
3. Evaporation
4. Sedimentation

Q9: True or false?

(a) A mixture of milk and water can be separated by filtration.

(b) A mixture of powdered salt and sugar can be separated by the process of winnowing.

(c) Separation of sugar from tea can be done with filtration.

(d) Grain and husk can be separated with the process of decantation.

Ans:

1. False
2. True
3. False
4. False