Chapter 3
SYNTHETIC FIBRES AND PLASTIC
1. Explain why some fibers are called synthetic.
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2. Mark (✓) the correct answer.
Rayon is different from synthetic fibres because
(a) it has a silk-like appearance.
(b) it is obtained from wood pulp.
(c) its fibres can also be woven like those of natural fibres.
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3. Fill in the blanks with appropriate words.
(a) Synthetic fibres are also called _______ or _______ fibres.
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(b) Synthetic fibres are synthesised from raw material called_____.
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(c) Like synthetic fibres. plastic is also a ________.
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4. Give examples which indicate that nylon fibres are very strong.
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5. Explain why plastic containers are favoured for storing food.
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6. Explain the difference between thermoplastic and thermosetting plastics.
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7. Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plugs/ switches/ plug boards
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8. Categorise the materials of the following products into 'can be recycled' and 'cannot be recycled'.
Telephone instruments, plastic toys cooker handles, carry bags, ball point pens, plastic covering on electrical wires, plastic chairs, electrical switches.
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9. Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana, giving your reason.
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10. Give examples to show that plastics are noncorrosive in nature.
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11. Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.
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12. 'Avoid plastics as far as possible'. Comment on advice.
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13. Match the terms of column A correctly with the phrases given in column B.
A B
(i) polyester (a) Prepared by using wood pulp
(ii) Teflon (b) Used for making parachutes and stockings
(iii) Rayon (c) Used to make non-stick cookwares
(iv) Nylon (d) Fabrics do not wrinkle easily
14. 'Manufacturing synthetic fibers is actually helping conservation of forests'. Comment.
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15. Describe an activity to shows that thermoplastic is a poor conductor of electricity.
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