Separation of Substances
Chapter – 5
Exercises (অনুশীলনী)
- Why do we need to separate different components of a mixture? Give two examples.
Ans:- The elements in the mixture need to be separated, because-
1) Non-use material has to be removed.
2) Impurities or harmful elements have to be removed.Example- Removing stones from rice,
Milk churning to separate butter.- what is winnowing? Where is it used?
Ans:- The method of separating the heavy and light components in a mixture by flowing into the air or air is called the process of harvesting.
This method is used to separate the thin rash or bark of heavy seeds (seeds) of the crop.
- How will you separate husk or dirt particles from a given sample of pulses before cooking.
Ans:- The bark or mold particles in the dal bought from the shop are washed with water before cooking, so that the impurities mixed with it, such as the soil roots and the dust, are separated. This process is known as the process of asraban.
- What is sieving? Where is it used?
Ans:- In the sieve process, the fine grains in a mixture are pierced with holes and large size impurities remain in the sieve.
The process of running the sieve is applied when the ingredients of the mixture are different in size. For example the process of running a sieve is used to separate the stones from the sand while building a house.- How will you separate sand and water from their mixture?
Ans:- If the water mixed with the sand is left in a single vessel for some time without stirring it, the sand will be deposited in the bottom of the utensil. (Sedimentation process)
- Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?
Ans:- It is possible to separate the sugar mixed with the flour powder. In this case we should use sieves. Due to the smaller lumps of the flour, the sieve rolls down and remains in the sieve as the sugar grains are larger.
- How would you obtain clear water from a sample of muddy water?
Ans:- If the murky water is left in a vessel for a while without moving it, the bark or such substance accumulates in the bottom of the water. (Sedimentation process)
If the water is not cleaned by the sedimentation process, the water can be cleaned using a small hole ing squirrel. (Filtration process)- Fill up the blanks
(a) The method of separating seeds of paddy from its stalks is called —————
Ans:- Dying.
(b) When milk, cooled after boiling, is poured onto a piece of cloth the cream (maim) is left behind on it. This process of separating cream from milk is an example of —————–
Ans:- The process of filtration.
(c) Salt is obtained from seawater by the process of ——————
Ans:- Evaporation.
(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The example is called —————-
Ans:- Filtration
- True or False?
(a) A mixture of milk and water can be separated by filtration.
Ans:- False.
(b) A mixture of powdered salt and sugar can be separated by the process of winnowing.
Ans:- False.
(c) Separations of sugar from tea can be done with filtration.
Ans:- False.
(d) Grain and husk can be separated with the process of decantation.
Ans:- False.
- Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add ice to the lemonade before or after dissolving sugar? In which case would it be possible to dissolve more sugar?
Ans:- Lemon juice and sugar are mixed with water and made in lemon syrup. Ice is added to this syrup to cool it down. The ice should be given after dissolving the sugar.