Separation Of Substances
Class 6th Science NCERT Exemplar Solution
- Paheli bought some vegetables such as French beans, lady’s finger, green chilies, brinjal…
- Boojho’s grandmother is suffering from diabetes. Her doctor advised her to take ‘Lassi…
- Which of the following mixtures would you be able to separate using the method of…
- Which amongst the following methods would be most appropriate to separate grains from…
- Four mixture are given below (i) Kidney beans and chick peas (ii) Pulses and rice (iii)…
- While preparing chapatis, paheli found that the flour to be used was mixed with wheat…
- You might have observed the preparation of ghee from butter and cream at home. Which…
- In an activity, a teacher dissolved a small amount of solid copper sulphate in a tumbler…
- During summer, Boojho carries water in a transparent plastic bottle to his school. The…
- Paheli asked for a glass of water from Boojho. He gave her a glass of ice cold water.…
- Sheela, Salma and Ravi have to dissolve maximum amount of sugar in the family amount of…
- Fill in the blanks with appropriate words: (i) Small pieces of stone can be removed from…
- State whether the following statement are True or false. (a) A mixture of oil and water…
- Name and describe briefly a method which can be helpful in separating a mixture of husk…
- Match the mixture in Column I with their method of separation in Column II.…
- Both Sarika and Mohan were asked to make salt solution. Sarika was given a teaspoonful of…
- Paheli was feeling thirsty but there was only a pot of water at home which was muddy and…
- Read the story titled ‘’ WISE FARMER’’ and tick the correct option to complete the story.…
- You are provided with a mixture of salt, sand, oil and water. Write the steps involved for…
- A mixture of iron nails, salt, oil, and water is provided to you. Give stepwise methods to…
Multiple Choice Questions
Question 1.Paheli bought some vegetables such as French beans, lady’s finger, green chilies, brinjal and potatoes all mixed in a bag. Which of the following methods of separation would be most appropriate for her to separate them?
A. Winnowing
B. Sieving
C. Threshing
D. Hand picking
Answer:
Hand picking is the method of separating easily identifiable material from a mixture. The components of the heterogeneous mixture can be separately identified from each other. And they can be separated from each other by by using hand picking. Thus vegetables can be easily identified and separated.
Question 2.
Boojho’s grandmother is suffering from diabetes. Her doctor advised her to take ‘Lassi ‘with less fat content. Which of the following methods would be most appropriate for Boojho to prepare it?
A. Filtration
B. Decantation
C. Churning
D. Winnowing
Answer:
Churning is a method from which cream i.e. fat content can be separated from the milk. So he should use churning process for preparing lassi.
Question 3.
Which of the following mixtures would you be able to separate using the method of filtration?
A. Oil in water
B. Cornflakes in milk
C. Salt in water
D. Sugar in milk
Answer:
Filtration method is used for separating insoluble substances from liquid. But a mixture of two liquids such as oil in water cannot be separated by this method. Also salt in water and sugar in milk are completely dissolved, so cannot be separated by filtration. So, cornflakes in milk can be separated by filtration.
Question 4.
Which amongst the following methods would be most appropriate to separate grains from bundles of stalks?
A. Hand picking
B. Winnowing
C. Sieving
D. Threshing
Answer:
The grains are separated from stalk (on which they grow) by the process of threshing. In this process stalks are beaten to separate grains from bundle of stalks. Being soft stalks can be broken and grains can be released.
Question 5.
Four mixture are given below
(i) Kidney beans and chick peas
(ii) Pulses and rice
(iii) Rice flakes and corn
(iv) Potato wafers and biscuits
Which of these can be separated by the method of winnowing?
A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iii)
D. (iii) and (iv)
Answer:
(iii) Rice flakes and corn
(iv) Potato wafers and biscuits
Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. Rice flakes and potato wafers are lighter substances in mixture, so these are separated from the given mixture by winnowing.
Question 6.
While preparing chapatis, paheli found that the flour to be used was mixed with wheat grains. Which out of the following is the most suitable method to separate the grains from the flour?
A. Threshing
B. Sieving
C. Winnowing
D. Filtration
Answer:
The most suitable method to separate the grains from the flour is by sieving. Sieving is used to separate those solid mixture which have components of different sizes.
Question 7.
You might have observed the preparation of ghee from butter and cream at home. Which method(s) can be used to separate ghee from the residue?
(i) Evaporation
(ii) Decantation
(iii) Filtration
(iv) Churning
Which of the following combination is the correct answer?
A. (i) and (ii)
B. (ii) and (iii)
C. (ii) and (iv)
D. (iv) only
Answer:
(ii) Decantation
(iii) Filtration
Explanation: by decantation and then by filtration ghee can be separated from the residue. Decantation is the process of pouring out the liquid without disturbing the sediment.
Question 8.
In an activity, a teacher dissolved a small amount of solid copper sulphate in a tumbler half filled with water. Which method would you use to get back solid back copper sulphate from the solution?
A. Decantation
B. Evaporation
C. Sedimentation
D. Condensation
Answer:
By the process of evaporation we can get back solid copper sulphate from the solution. The process of evaporation for separating a mixture is based on the fact that liquids vaporize easily whereas solids do not.
Question 9.
During summer, Boojho carries water in a transparent plastic bottle to his school. The bottle still had some water left in it. The following day, He observed some water droplets on the inner surface day, he observed some water droplets on the inner surface of the empty portion of the bottle. These droplets of water were formed due to
A. Boiling and condensation.
B. Evaporation and condensation.
C. Evaporation and saturation
D. Condensation and saturation.
Answer:
The droplets of water on the inner surface of bottle were formed due to evaporation and condensation. The process of conversion of water vapor into liquid is called condensation.
Question 10.
Paheli asked for a glass of water from Boojho. He gave her a glass of ice cold water. Paheli observed some water droplets on the outer surface of water were formed? Which of the following should be Boojho’s answer?
A. Evaporation of water from the glass.
B. Water that seeped out from the glass.
C. Evaporation of atmospheric water vapor.
D. Condensation of atmospheric water vapor.
Answer:
Water droplets on the outer surface are formed due to condensation of atmospheric water vapor. Actually the water vapor present in air on coming in contact with the cold glass of water, loses energy and gets converted to liquid state, which we see as water droplets.
Very Short Answer Questions
Question 1.Sheela, Salma and Ravi have to dissolve maximum amount of sugar in the family amount of milk so as to win in a game. Ravi took hot boiling milk while Saima took ice cold milk. Sheela managed to get milk at room temperature. Whom do you thick would win the game and why?
Answer:
Ravi would win the game because Ravi took hot boiling milk and hot boiling milk at higher temperature would dissolve more amount of sugar and also solubility increases with temperature. So, Ravi would be able to dissolve maximum amount of sugar in milk.
Question 2.
Fill in the blanks with appropriate words:
(i) Small pieces of stone can be removed from rice by ……………… .
(ii) …………….. are obtained from stalks by threshing.
(iii) Husk from wheat flour is generally removed by ………………. .
(iv) The process of settling of heavier particles is called ………………. .
(v) Filtration is helpful in separating an insoluble ………………. From a ………………….. .
Answer:
(i) Small pieces of stone can be removed from rice by handpicking
Hand picking is the method of separating easily identifiable material from a mixture. The components of the heterogeneous mixture can be separately identified from each other.
(ii) Grains are obtained from stalks by threshing.
The grains are separated from stalk (on which they grow) by the process of threshing. In this process stalks are beaten to separate grains from bundle of stalks. Being soft stalks can be broken and grains can be released.
(iii) Husk from wheat flour is generally removed by sieving.
Sieving is used to separate those solid mixture which have components of different sizes.
(iv) The process of settling of heavier particles is called sedimentation.
The process of settling or being deposited as a sediment.
(v) Filtration is helpful in separating an insoluble solute (solid) from a solution (liquid).
Filtration is any of various mechanical, physical or biological operations that separate solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass.
Question 3.
State whether the following statement are True or false.
(a) A mixture of oil and water can be separated by filtration.
(b)Water can be separated from salt by evaporation.
(c) A mixture of wheat grains and wheat flour can be separated by sieving.
(d) A mixture of iron filing and rice can be separated by magnet.
(e) A mixture of wheat grains and rice flakes can be separated by winnowing.
(f) A mixture of tea leaves and milk can be separated by decantation.
Answer:
(a) false
A mixture of oil and water can be separated by decantation. Decantation is the process of pouring out the liquid without disturbing the sediment.
(b) true
The process of evaporation for separating a mixture is based on the fact that liquids vaporize easily whereas solids do not.
(c) true
Sieving is used to separate those solid mixture which have components of different sizes.
(d) true
iron gets attracted to the magnets since they are polar particles.
(e) true
winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air.
(f) true
Decantation is the process of pouring out the liquid without disturbing the sediment.
Short Answer Questions
Question 1.Name and describe briefly a method which can be helpful in separating a mixture of husk from grains. What is the principle of this method?
Answer:
Winnowing is used to separate lighter husk particles from heavier grains by wind or blowing air. The method is based on the fact that husk is very light whereas wheat grains are comparatively heavy. The mixture is allowed to fall from a height by shaking winnowing basket continuously. The husk particles are carried away by wind to a greater distance. The wheat grains, being heavy, fall down vertically to the ground and form a heap of wheat grains.
Question 2.
Match the mixture in Column I with their method of separation in Column II.
Answer:
(a) - (iii)
Decantation is the process of pouring out the liquid without disturbing the sediment.
(b) - (iv)
iron gets attracted to the magnets since they are polar particles.
(c) - (v)
The process of evaporation for separating a mixture is based on the fact that liquids vaporize easily whereas solids do not.
(d) - (ii)
Hand picking is the method of separating easily identifiable material from a mixture. The components of the heterogeneous mixture can be separately identified from each other.
(e) - (i)
Sieving is used to separate those solid mixture which have components of different sizes.
Long Answer Questions
Question 1.Both Sarika and Mohan were asked to make salt solution. Sarika was given a teaspoonful of salt and half a glass of water. Whereas Mohan was given twenty teaspoon full of salt and half a glass of water.
Answer:
Sarika and Mohan will mix salt with water within a certain amount to make salt solution. Hence, Sarika will make a better salt solution.
Saturation is a point at which a substance cannot dissolve no more of a substance and additional amount of that substance will appear as a precipitate. Mohan’s solution would be saturated because in his case, some salt would remain undissolved and settled at the bottom of the glass.
Question 2.
Paheli was feeling thirsty but there was only a pot of water at home which was muddy and unit for drinking. How do you think Paheli would have made this water fit for drinking if the following materials were available to her.
Alum, tub, muslin cloth, gas stove, thread, pan and lid.
Answer:
Paheli can make this water fit for drinking by working on the following sequence:
Question 3.
Read the story titled ‘’ WISE FARMER’’ and tick the correct option to complete the story.
A farmer was sad/happy to see his healthy wheat crop ready for harvest. He harvested the crop and left it under the sun/rain to dry the stalks. To separate the seeds from the bundles of the stalk he handpicked/threshed them. After gathering the seed grains he wanted to separate the stones and husk from it. His wife winnowed / threshed them to separate the husk and later sieved/handpicked to remove stones from it. She ground the wheat grains and sieved/filtered the flour. The wise farmer and his wife got a good price for the flour. Can you tell why?
Answer:
1. Happy
2. Sun
3. Threshed
4. Winnowed
5. Handpicked
6. Sieved
They got a good price as they used appropriated methods of separation to get good quality of flour (Atta).
Question 4.
You are provided with a mixture of salt, sand, oil and water. Write the steps involved for the separation of salt, sand and oil from the mixture by giving an activity along with the diagram.
Answer:
Steps for the separation of salt, sand, oil and water
First we will use decantation method to separate oil and water. Water being heavier, forms the lower layer and oil being lighter forms the upper layer in the beaker. We can decant off the upper layer of oil into another beaker carefully.
Then by the process of filtration sand can be separated from water. The filtrate obtained contains the mixture of salt and water. The salt dissolved in water can be separated by the process of evaporation. The water present in the salt solution and then the salt is left behind.
Question 5.
A mixture of iron nails, salt, oil, and water is provided to you. Give stepwise methods to separate each component from this mixture?
Answer:
Steps for the separation of iron nails, salt, oil, and water
Iron nails are separated from the mixture by using magnets. Then by using decantation oil and water is separated. Oil being lighter forms the upper layer in the beaker and we can decant off the upper layer of oil.
Now the mixture contains dissolved salt and water. Salt can be obtained from the water by the process of evaporation. The water present in the salt solution will form water vapor and then the salt is left behind.