CBSE – 8th Standard Science

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Question Bank – Chapter 3 – Synthetic Fibres and Plastics

Chapter 3 

SYNTHETIC FIBRES AND PLASTICS

 

Qus 1. How do we get natural fibres?

Ans. Natural fibres like cotton, wool, silk, etc., are obtained from  plants or animals.

 

 

Qus 2. How are synthetic fibres made?

Ans. The synthetic fibres, are made by human beings that is why these are called synthetic or man-made fibres.

 

Qus 3. What is rayon or artificial silk?

Ans.A fibre having the properties similar to that of silk, such a fibre is obtained by chemical treatment of wood pulp. This fibre is called rayon or artificial silk.

 

Qus 4. Which was the first fully synthetic fibre?

Ans. Nylon was the first fully synthetic fibre.

 

Qus 5. What nylon is very popular for making clothes?

Ans.  Nylon fibre is  strong, elastic and light. It is lustrous and easy to wash. So, it is very popular for making clothes.

 

Qus 6. What is the main advantage of making dress material from polyester?

Ans. Fabric made from polyester does not get wrinkled easily it remains crisp and is easy to wash so, it is quite suitable for making dress material from polyester

 

Qus 7. What is an ester?
Ans. Polyester is actually made up of the repeating units of a chemical called an ester.

 

 

Qus 8. What makes synthetic fibres more popular than natural fibres?

Ans. Synthetic fibres are more durable and affordable which makes them more popular than natural fibres.

 

Qus 9. What are petrochemicals?

Ans. All the synthetic fibres are prepared by a number of processes using raw materials of petroleum origin, called petrochemicals.

 

Qus 10. What are thermoplastics?

Ans. Such plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics.

  

Qus 11. Write two examples of thermoplastics?

Ans. Polythene and PVC are some of the examples of thermoplastics.

 

Qus 12. What are thermosetting plastics?

Ans. Plastics which when moulded once cannot be softened by heating. These are called thermosetting plastics.

 

Qus 13. What is Teflon?

Ans. Teflon is a special plastic on which oil and water do not stick. It is used for nonstick coating on cookwares.

 

Qus 14. What do you mean by biodegradable?

Ans. A material which gets decomposed through natural processes, such as action by bacteria, is called biodegradable.

  

Qus 15. Explain the term ‘non-biodegradable’?

Ans. A material which is not easily decomposed by natural processes is termed as non-biodegradable.

 

TRY THESE :-

 

Q.1  Name the polymer which occurs naturally?

Q.2  Although rayon is obtained from natural source wood pulp, even the it is a synthetic fibre?

Q.3  Name the chemical used to make polyester ?

Q.4  Write the properties and uses of nylon

Q.5  By which material artificial wool is formed, why is it more popular than natural wool?

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