Science Class 8th Test From Chapter 3 – Synthetic Fibres and Plastics
M.M: 41 marks Dated: 02/07/2011
Time: 1 hour
Q 1: Fill in the blanks (1 mark each x 17 = 17 marks, depending on your answer, more than one word may come at certain blanks).
i. A very thin, thread like strand from which cloth is produced
in called a ______________.
ii. Based on the source from which the fibres are obtained, there can be two types of fabrics: ____________ and ____________.
iii. The three R’s, i.e. RRR, used to save the environment from the harmful effects of excessive use of plastics, stand for ____________, _____________ and ______________.
iv. The use of plastics can be minimised by using bags of _______________ or ____________ instead of polythene bags.
v. The full form of PVC is _______ _________ _____________.
vi. In ______________, the long polymer chains are not cross linked with each other.
vii. ______________ plastics are used for making articles which cannot get hot during use and are hard and rigid too.
viii. ___________ is a type of plastic on which oil and water does not stick and can withstand high temperatures.
ix. __________ is a type of plastic which is very hard, tough, poor conductor of heat and electricity and is used for making the handles of various cooking utensils.
x. Synthetic fibres are produced from raw materials called ________________.
xi. Synthetic fibres are also called ___________ or ___________ fibres.
xii. ______________ is a synthetic fibre produced from chemical “acrylonitrile’, is soft, warm with a feel like wool.
xiii. PET stands for ______________ __________________.
xiv. _____________ is made of repeating units of chemical called ester.
xv. The name NYLON is based on the fact that it was developed in _______________ and __________.
xvi. _____________ is often regarded as artificial silk.
xvii. A ___________ is a very big molecule which is formed by combining large number of small molecules.
Q 2: Give two examples each of synthetic and natural fibres.
(2 marks)
Q 3: Define petrochemicals. Give two examples. (2 marks)
Q 4: Is Rayon an artificial fibre or a natural fibre? How is it different from truly synthetic fibres? (2 marks)
Q 5: Which was the first fully synthetic fibre made by man without any use of natural raw material? Write two uses of the same.
(2 marks)
Q 6: What is polycot and polywool made of? (1 mark)
Q 7: Write two properties of PET and two uses of the same.
(2 marks)
Q 8: Write two pros and two cons of synthetic fibres. (2 marks)
Q 9: Write one difference between thermosetting plastics and thermoplastics. Write two examples of both of them. (3 marks)
Q 10: Show arrangement of polymer chains in thermoplastics and thermosetting plastics. (2 marks)
Q 11: Which of the following articles made of plastics “Cannot be recycled” and which “Can be recycled”? Items: Telephone instruments, Plastic chairs, Carry bags, Electrical switches, Ball point pens, Plastic insulation on electrical wires. (3 marks)
Q 12: What do you understand by non-biodegradable and biodegradable materials? Give two examples of each. (3 marks)
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