Fibres and Plastics
Q23. Why is nylon used for making parachutes and ropes for rock
Nylon is used for making parachutes and ropes for rock climbing because nylon
fibre is strong and can hold heavy weight.
Q24. What is polymer?
Ans. Synthetic fibres and plastics, like natural
fibres, are made of very large units called polymers. Polymers are made up of
many smaller units.
Q25. Define petrochemicals.
All the synthetic fibres are prepared by a number of processes using raw materials
of petroleum origin, called petrochemicals.
Q26. Why should we use a cotton carry bag or jute bag while
going for shopping?
Ans. We should use cotton or jute bags while going for
shopping in order to minimise the use of plastic bags.
Q27. Why plastic articles are available in all shape and size?
Plastic articles are available in all possible shapes and sizes because plastic
is easily mouldable i.e. can be shaped in any form.
Q28. Why is teflon used for nonstick coating on cookwares?
Which material is used for coating non-stick kitchen wares and
Ans. Teflon is used for nonstick coating on cookwares
because it is a special plastic on which oil and water do not stick.
Q29. Explain why plastic containers are favoured for storing
Ans. Plastic containers are favoured for storing food
because of their light weight, lower price, good strength and easy handling.
Q30. What is PET? Write its uses.
Ans. PET is a very familiar form of polyester. It is
used for making bottles, utensils, films, wires and many other useful products.
Q31. Give the composition of Polycot and Polywool.
Ans. Polycot is a mixture of polyester and cotton.
is a mixture of polyester and wool.
Q32. “Tin, aluminium and other metal can are considered
non-biodegradable.” Give reason.
Ans. Tin, aluminium and other metal can are considered
non-biodegradable because they approximately take 100 to 500 years to
Q33. Give two uses of rayon.
Ans. Uses rayon
It is mixed with cotton to make bed sheets.
It is mixed with wool to make carpets.
Q34. Suggest some ways in which we can contribute towards reducing
the use of plastic materials?
Ways to reduce use of plastic materials
Avoid the use of plastics as far as
Make use of bags made of cotton or jute
when you go for shopping.
Q35. Give examples to show that plastics are noncorrosive in
Why are the chemicals in the laboratory stored in plastic
Why are plastic containers used to store chemicals in labs?
Plastics do not react with water and air. They are not corroded easily. That is
why they are used to store various kinds of material, including many chemicals.
Q36. What type of cookware is used in microwave oven and why?
Ans. Special plastic cookware is used in microwave
ovens for cooking food. In microwave ovens, the heat cooks the food but does
not affect the plastic vessel.
Q37. How is plastic useful in healthcare industry?
Plastics find extensive use in the health-care industry. Some examples of their
use are the packaging of tablets, threads used for stitching wounds, syringes,
doctors’ gloves and a number of medical instruments.
Q38. Why is melamine used for making floor tiles, kitchenware
and fabrics which resist fire?
Ans. Melamine is a versatile material. It resists fire
and can tolerate heat better than other plastics. It is used for making floor
tiles, kitchenware and fabrics which resist fire.
Q39. Why electrical wires have plastic covering, and handles of
screw drivers are made of plastic?
Ans. Plastics are poor conductors of heat and
electricity. That is why electrical wires have plastic covering, and handles of
screw drivers are made of plastic.
Q40. Why should recycled plastic not be used for the storage of
Why is recycled plastic not suitable for storage of food items?
Can recycled plastics be used in food containers? Why or why
Ans. Most of the thermoplastics can be recycled. However,
during recycling certain colouring agents are added. This limits its usage
especially for storage of food.