Question

please find the extra question

Answer 1

What are the use of fabrics?
Ans- making clothes.

2* what other name is used for synthetic fibres?
Ans. - Man made fibres and artificial fibres.

3*why artificial fibres are made??
Ans - because of ever increasing demand of fibre and fabrics.

4*what is the use of natural fibres?
Ans - use of making fabrics

5*Name household articles??
Ans 1. ROPES
........ 2.CARPETS.

6.Give examples of some fabrics?
ANS - Cotton, jute, silk. Etv

7*From where fabrics obtained?
Ans - Obtained from natural sources.

Hope it helpful.

Answer 2

1.Name the two types of fibres.
Ans – Natural fibres and synthetic fibres

2. What are natural fibres?
Ans – Natural fibres are the fibres which come from natural sources like plants and animals.

3. Name some natural fibres obtained from plants.
Ans – Cotton, linen, hemp, jute, flax, rhea, silk cotton (simbal), coir etc…

4. Name some natural fibres which are obtained from animals.
Ans – Wool, silk etc…

5. What are synthetic fibres?
Ans – Synthetic fibres are man-made fibres.

6. Each kind of synthetic fibre or material has its own properties. Give reason.
Ans – Each kind of synthetic fibre or material has its own properties because synthetic fibres are made from different chemicals.

7. Synthetic material is known as …………….. .
Ans – Plastic

8. Name the type of fibres which are more in length and are long lasting.
Ans – Synthetic fibres

9. Name the limitation with synthetic fibres.
Ans – Synthetic fibres are poor (not good) absorbents of moisture and they catch fire easily.

10. Define monomer.
Ans – A substance having a single unit structure forming its particle is called a monomer. (mono or monos meaning single ; mer meaning unit).

11. What is polymerization?
Ans – The process of joining together of monomers to form a polymer is called polymerization.

12. Name the two ways in which monomers combine to form a polymer.
Ans – The two different ways by which monomers combine to form a polymer are :

a. Linear polymers – like beads on a string

b. Cross-linked polymers – like beads on a net

13. A single unit or a monomer of a substance is its …………. .
Ans – Molecule

14. Name the two types of polymers.
Ans – Natural polymers and synthetic polymers

15. Explain natural polymers briefly.
Ans – Natural fibres like cotton, wool and silk are polymers. Cotton is a polymer of glucose. Wool and silk are the polymers of amino-acids (proteins). Natural polymers may not be plastic in nature.

16. Explain synthetic polymers briefly.
Ans – Synthetic polymers are made from chemical substances in laboratories or factories. Synthetic polymers are plastic in nature. Nylon and polyester are synthetic fibres.

Eg: – Ethylene (gas) is a monomer obtained from petroleum. Its chemical formula is CH₂. During polymerization, many units of ethylene get linked to form a chain. This polymer is polyethylene, a kind of plastic, commonly known by the name of polyethene.

A polymer chain may be made of similar units.

Eg: – Polyethylene

Some polymers may be made from two or more different kinds of units.

Eg: – Nylon which is made from a unit of amine (CHN) and adipic acid (CHO).

Scientists evolved a mechanism  to polymerize the monomers of certain substances like rubber, silicone, rosins (exuded from trees) and petroleum products such as ethane, propane, benzene, toluene, styrene, esters and others. All these are the raw material for synthetic plastics.

17. Name the first materials to be used for clothings in the east (including India).
Ans – Cotton, wool and silk

18.  Name the first materials to be used for clothings in the west.
Ans – Leather, wool and fur

19. How are most synthetic fibres obtained?
Ans – Most synthetic fibres are obtained from petroleum products, natural gas and coal by the process of polymerization.

20. Rayon is prepared from ………….. .
Ans – Cellulose

21. How is cellulose obtained?
Ans – Cellulose is obtained from cotton, wood and other plant products.

22. Cellulose is a natural polymer but rayon made from it is considered a synthetic fibre. Give reason.
Ans – Though cellulose is a natural polymer but rayon made from it is considered a synthetic fibre because cellulose needs extensive chemical treatment to form rayon.

23. Give an example of a semi-synthetic fibre.
Ans – Rayon

24. Rayon is known as synthetic silk. Give reason.
Ans – Rayon has silk-like appearance.

25. What is a polymer?
Ans – A polymer is a substance having a large molecule made of many smaller molecules (called monomers) linked together.

26. Name the naturally occurring polymer which composes cotton.
Ans – Cellulose

27. Name the naturally-occurring fibre which composes the walls of all plant cells.
Ans – Cellulose

28. Name the naturally-occurring fibre present in wood.
Ans – Cellulose

29. How is rayon obtained?
Ans – Rayon is obtained by chemical treatment of wood pulp.

30. Mention the uses of rayon.
Ans – Rayon is used to make clothing, curtains, car upholstery and carpets.


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