1. Explain why some fibres are called synthetic.
2. Mark (tick) 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.
3. Fill in the blanks with appropriate words.
(a) Synthetic fibres are also called _______ or ________
fibres.
(b) Synthetic fibres are synthesised from raw material called ___________.
(c) Like synthetic fibres, plastic is also a ___________.
4. Give examples which indicate that nylon fibres are very strong.
5. Explain why plastic containers are favoured for storing food.
6. Explain the difference between thermoplastic and thermosetting plastics.
7. Explain why the following are made of thermosetting plastics,
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
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 bowls, plastic covering on electrical wires, plastic chairs.
electrical switches.
Answers
Answer:
5) Plastic containers are favoured for storing food due to the following reasons : Plastic containers are lightweight. They do not react with the food items and so safer to store unlike aluminium which reacts with lemon pickles. It has good strength,durability and quality.
4) As nylon is a very strong fibre, it is used for making parachutes, rock climbing ropes, fishing nets, seat belts. A nylon thread is actually stronger than steel wire.
1) Some fibres are called synthetic because they are not made from natural fibres. Instead, they are made by chemical processing of petrochemicals. The synthetic fibres are made up of very large units called polymers. Some of the synthetic fibres are - nylon, rayon, acrylon.
Answer:
2) option a
others I dont know!