Very Short Answers - Synthetic Fibres and Plastics, Science, Class 8 | Advance Learner Course: Science Class 7 PDF Download

VERY SHORT ANSWER TYPE QUESTIONS
 

Q. 1. What are clothes made up of ?
 Ans. The clothes we wear are made of fabrics.

Q. 2. What are fabrics made up of?
 Ans. The fabrics are made of fibres.
 

Q. 3. How many types of sources of fibre are there?
 Ans. There are two types of sources of fibres:
(i) Natural sources
(ii) Artificial sources.
 

Q. 4. What are natural fibres?
 Ans. The fibres obtained from plants or animals are called natural fibres.

Q. 5. Give two examples of natural fibres.
 Ans. (i) Cotton (ii) Jute.
 

Q. 6. What are synthetic fibres?
 Ans. The fibres made by human beings are called synthetic or man-made fibres.
 

Q. 7. Name two man-made fibres.
 Ans. (i) Nylon (ii) Rayon.
 

Q. 8. What are polymers?
 Ans. When a large number of small units combine to form a single large unit, then the large unit is called polymer.
 

Q. 9. What is the word meaning of polymer?
 Ans. Polymer consists of two words, poly and mer. Poly means many and mer means repeating units.

Q . 10. Name a natural polymer.
 Ans. Cellulose.

Q . 11. What are the units of cellulose?
 Ans. Cellulose is made up of a large number of glucose units.
 

Q . 12. Name the fibre having properties similar to that of silk.
 Ans. Rayon.
 

Q . 13. What is the common name of rayon?
 Ans. Rayon is known as artificial silk.

Q . 14. How is rayon obtained?
 Ans. Rayon is obtained by chemical treatment of wood pulp.
 

Q . 15. Name a man-made fibre which is made without using natural raw materials.
 Ans. Nylon.
 

Q . 16. When was nylon made?
 Ans. Nylon was made in 1931.
 

Q . 17. What are the raw materials used in making nylon?
 Ans. Nylon is prepared from coal, water and air.

Q . 18. Which is the first fully synthetic fibre?
 Ans. Nylon.

Nylon

Q . 19. Name two articles made by rayon.
 Ans. Socks and tents.
 

Q . 20. Write the names of two articles made by nylon.
 Ans. Parachutes and ropes for rock climbing.
 

Q . 21. Name a polyester which is commonly used.
 Ans. Terylene is a popular polyester.

Q . 22. What is polyester?
 Ans. The polymer made up of the repeating units of ester.
 

Q . 23. Which is more stronger, a wire of steal or a wire of nylon?
 Ans. Wire made of nylon.
 

Q . 24. Name a synthetic fibre which works like wool.
 Ans. Acrylic.
 

Q . 25. What are petrochemicals?
 Ans. All the synthetic substances which are formed by using petrolium as raw material are called petrochemicals.
 

Q . 26. What are plastics?
 Ans. The plastics are a polymer like the synthetic fibres which are mouldable.
 

Q . 27. How many types of arrangement of units are in plastics? Name them.
 Ans. There are two types of arrangement of units in plastics:
(i) Linear linking (ii) Cross linking.
 

Q . 28. Name two types of plastics.
 Ans. (i) Thermoplastics (ii) Thermosetting plastics.
 

Q . 29. Give two examples of thermoplastics.
 Ans. Polythene and PVC.

Q . 30. What is the full form of PVC?
 Ans. PVC stands for Poly Venyl Chloride.

Q . 31. Name two thermosetting plastics.
 Ans. Bakelite and Melamine.
 

Q . 32. Why plastics are not ecofriendly?
 Ans. Plastics take several years to decompose, so they are not ecofriendly.
 

Q . 33. What are 4Rs?
 Ans. 4Rs stand for Reduce, Reuse, Recycle and Recover.