DAV Class 6 Science Solution Chapter 4 Separation of Substances

DAV Class 6 Science Solution Chapter 4 Separation of Substances

DAV School Books Class 6 Science Solution Chapter 4 Separation of Substances all Question Answer. DAV Class 6 4th Chapter Separation of Substances full Chapter explanation by expert teacher.

DAV School Books Class 6 Science Solution Chapter 4 Separation of Substances:

(A) Fill in the blanks.

Answer: (1) hand packing.

Answer: (2) evaporation.

Answer: (3) filtration.

Answer: (4) loading.

Answer: (5) centrifugation.

(B) Match the following:

Answer:

(1) Wind:- (b) winnowing.

(2) Chalk powder and water:- (c) sedimentation.

(3) Oil and water :- (e) separating funnel.

(4) Separating peas from cooked pulao:- (a) hand picking.

(5) Muslin cloth:- (d) filtration.

(6) Camphor and salt:- (f) sublimation.

(C) Tick (✓) the correct option.

(1) Which of the following is an example of a heterogeneous mixture?

Answer:- (b) Pebble in rice.

(2) Which one of the following is not an example of a pure substance?

Answer:- (a) Oxygen.

(3) The process of loading helps to ______.

Answer:- (b) speed up the rate of sedimentation.

(4) Transferring the clear liquid into another container, leaving behind the residue, is called ______.

Answer:- (b) Decantation.

(5) A substance that sublimes easily, is _____.

Answer:- (a) Naphthalene.

D.) Answer the following questions in brief.

(1) Name any three methods used for separating a solid-solid mixture.

Answer:- The method of separating solid from solid are handpicking method, sublimation method, and threshing method.

(2) What is winnowing? Give an example of a mixture whose components can be separated by this method.

Answer:- Winnowing is a method of separation of solid with solid with this method we can separate lighter husks from heavier grains. We can separate wheat and husk by this method.

(3) Some iron pins get scattered on the carpet when you are expecting guests. How can one collect all the pins in the shortest possible time?

Answer:- For collecting the iron pins I will use the magnetic separation method.

(4) Name any three substances which sublime on heating.

Answer:-

(1) Camphor

(2) Naphthalene balls

(3) Iodine

(5) What crystallisation? Name any three substances which can be purified using this technique.

Answer:- Crystallization is a process of separation of solid in the form of crystal from a saturated solution. Sugar and salt can be separated by using this method

(E) Answer the following questions.

(1) Differentiate between a pure substance and a mixture. Give two examples of each.

Answer:-

• Pure substance –

Pure substance is made up of only 1 substance Pure substance cannot be separated Examples – sugar, water, salt

• Mixture –

When two or three substances mixed together in any proportions that time mixture is formed. Mixtures can be separated.

Examples – milkshake, crude oil

(2) State the difference between heterogeneous and homogeneous mixtures. Give two examples of each type.

Answer:-

• Heterogeneous mixture –

Heterogeneous mixtures have different composition over its different parts Example – solution of oil and water

• Homogeneous mixture –

A mixture having the same composition over its all parts Example – solution of salt and water

(3) Can a mixture of iodine and camphor be separated by the sublimation method? Give reason for your answer.

Answer:- Yes mixture of iodine and camphor be separated by the sublimation because, We know that iodine and camphor both are sublime substances so we can’t separate them by sublimation process because by sublimation method iodine and camphor will convert into the gas and after conversion into gas we can’t separate it

(4) Why does the size of naphthalene balls, put in open, keep on reducing with time?

Answer:- Naphthalene balls are a sublime substance when it comes in contact with air they start reducing by sublimation process.

(5) After a dust storm, how does rain help in making air clear?

Answer:- After a dust storm when rain comes it helps in cleaning the air because when rain combines with dust they become heavier and come down on the ground and air becomes clean.

(6) Sawdust, mixed in water, cannot be separated by the sedimentation method. Why?

Answer:- Sawdust cannot be separated by using sedimentation method because sawdust is lighter in weight and can’t settle down.

(7) The filtration method cannot be used to separate sugar and salt mixed in water. Why?

Answer:- Filtration method is used for the separation of solid and liquid but the solids should be insoluble in liquid but the sugar is soluble in water hence it can’t be separated by using filtration method.

(8) Describe the method of centrifugation using an appropriate example.

Answer:- Centrifugation method is used to separate the fine solid particles in liquid by rotating them in High speed for some time

Example – separation of butter from milk.

Value based questions

Q.) The students of Class-VI, participated actively in the ‘Swachata Abhiyan’ for their school and its neighbourhood. They separated out the biodegradable and non-biodegradable wastes and put them in separate bins. Their science teacher appreciated their work. She compared their work with the methods of ‘Sieving’ and ‘Winnowing’ about which she had taught them last week.

(1) State the values displayed by the students of Class-VI.

Answer:- cleanness, dedication, discipline.

(2) Give one example each of a situation in which ‘sieving’ and ‘winnowing’ can be used for bringing about the required separation.

Answer:-

One example of sieving:- sieving of sand.

One example of winnowing:- winnowing of paddy.

Something To Do

(2) Fill a glass with impure water. Using your knowledge of methods of separation, suggest a method to purify it. Justify your suggestions.

Answer:- For purification of impure water we can filter it by using a strainer or we can use Alum to separate the impure particles from water. By using Alum the impure particles settle down and we can use the above water which is purified

(3) Suggest ways to separate the components of the following mixtures.

Answer:-

(a) Camphor, sand and salt.

Camphor :- sublimation

Salt :- evaporation Sand :- filtration.

(b) Sawdust, common salt and iron nails.

Sawdust :- filtration Common salt :- evaporation Iron nails :- remaining thing.

(C) Ammonium chloride, common salt and chalk powder.

Ammonium chloride: sublimation Common salt: evaporation

Chalk powder: filtration.

(4) Visit the kitchen in your house and also your surroundings. Observe the different methods of separation that are being used by different people. Make a list of your observations and name the different methods used in different cases.

Answer:-

(1) A filtration method is used to filter the water.

(2) The filtration method is also used for tea by using a strainer.

(3) The evaporation method is used to remove water from rice.

(4) Hand picking method is used to remove the stone particles from wheat, rice, grains etc.

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