Synthetic Fibres and Plastics

Q1. Fill in the blanks.

                           i.        Synthetic fibres are also called artificial or man-made fibres.

                          ii.        Synthetic fibres are synthesised from raw material called petrochemicals.

                         iii.        Like synthetic fibres, plastic is also a polymers.

                         iv.        Terylene is a popular polyester.

                          v.        Polymer is made of many repeating units.

Q2. True/False

                           i.        Thermoplastics can bent easily. True

                          ii.        Polymers are made up of many bigger units. False

                         iii.        PET is a very familiar form of polyester. True

                         iv.        Polyester fabrics do not get wrinkled easily. True

                          v.        Fabric obtained from silk fibre is very cheap. False

                         vi.        Fabric made from polyester fibre does not get wrinkled easily. True

Q3. Name the plastic whose sheets are used for packing liquids.

Ans. Polythene

Q4. Name one naturally occurring polymer.

Ans. Cellulose

Q5. Name the fibre used for making parachutes and ropes for rock climbing.

Ans. Nylon

Q6. Which synthetic fiber is known as artificial silk?

Ans. Rayon fiber is known as artificial silk.

Q7. Which is the first fully synthetic fibre?

Ans. Nylon is the first fully synthetic fibre.

Q8. Write one disadvantage of synthetic fibre.

Ans. Synthetic fibres melt on heating.

Q9. What are esters?

Ans. Esters are the chemicals which give fruits their smell.

Q10. What are the 4 R in waste management?
Or
What are the 4 R's principles of plastic?

Ans. 4 R principles mean Reduce, Reuse, Recycle and Recover.

Q11. What are the advantages of nylon?

Ans. Nylon fibre is strong, elastic and light. It is lustrous and easy to wash.

Q12. Write uses of bakelite.

Ans. It is used for making electrical switches, handles of various utensils, etc.

Q13. Write uses of melamine.

Ans. It is used for making floor tiles, kitchenware and fabrics which resist fire.

Q14. How is rayon different from synthetic fibres?

Ans. Rayon is different from synthetic fibres because it is obtained from a natural source, wood pulp.

Q15. Give examples which indicate that nylon fibres are very strong.

Ans. Nylon fibres are very strong as it is used to make parachutes and ropes for rock climbing.

Q16. What is polythene?

Ans. Polythene (Poly + ethene) is a type of plastic that is used for making commonly used polythene bags.

Q17. Is plastic bag non-biodegradable? Why?

Ans. Plastic bag is non-biodegradable because it takes several years to degenerate.

Q18. Can we store jams and pickles in plastic containers? Give reason.

Ans. We can store jams and pickles in plastic containers because plastics do not react with water and air and do not get corroded easily.

Q19. Do all plastics have same type of arrangement of units?

Ans. All plastics do not have the same type of arrangement of units. In some it is linear, whereas in others it is cross-linked.

Q20. Why nylon is called fully synthetic fibre?

Ans. Nylon is called fully synthetic fibre because it is prepared from coal, water and air.

Q21. What is polyester?

Ans. Polyester (Poly+ester) is actually made up of the repeating units of a chemical called an ester.

Q22. Write one use of acrylic.

Ans. Acrylic is used as a substitute of natural wool for knitting sweaters, shawls, blankets etc.