chapter 3 Synthetic Fibres and Plastics #Class_8_Science_mission
A. Multiple choice questions.
1. Which of these is thermoplastic in nature? (a) Teflon (b) Rayon (c)
Bakelite (d) Polythene
2. To make a pan non-stick, we should get it coated with (a) Bakelite (b)
Teflon (c) Rayon (d) Polythene
3. Poly wool fibre is (a) Natural (b) Synthetic (c) Monomer (d)
Blended
4. The plastic that cannot be molten or moulded on giving it a shape is
(a) Thermoplastic (b) Polyurethane (c) Thermoset (d) Acrylic
5. Raw material for rayon comes from (a) Cellulose (b) Coal (c) Petroleum
(d) Animal bones
Ans: 1. d 2. b 3.
b 4. c 5. c
B. Match the following:
|
Column A |
Answer |
Column B |
|
1. Rayon 2. Teflon 3. Acrylic 4. Polycot 5. Polyurethane 6. Polystyrene |
1. c 2. d 3. e 4. f 5. b 6. a |
a. Thermocol b. Mattresses c. Dress material d. Non-stick cookware lining e. Synthetic knitting wool f. Blended dress material. |
C. Fill in the blanks
1. Wool is a ... fibre.
2. Base raw material for rayon is ………….
3. Plastic made from ethylene is called
4. Tensile strength of nylon is.............. than that of cotton.
5. Melamine is a..... plastic.
6. A mixture of fibreglass and
rayon is used in…….
7………… is the synthetic fibre used as wool.
8. ………… is known as artificial silk.
9. Teflon is. ………….. plastic.
10. Polymer is a long chain of... …………
Ans: 1. natural 2. cellulose 3. polyethylene 4.
greater 5. Thermoset
6. helmets 7.
Acrylic 8. Rayon 9. Thermoset 10. monomers
D. State whether 'true' or 'false'.
1. Man-made fibres are synthetic fibres. True
2. Polymers are a chain of monomers. True
3. Plastics do not corrode or rust. True
4. Most plastics are biodegradable. False
5. Plastics are good conductors of electricity. False
6. Plastic melamine is fire resistant. True
7. Bakelite is a soft and flexible plastic. False
8. Cellulose is a natural polymer. True
9. Synthetic fibres shrink on
washing. False
10. Acrylic wool is a synthetic fibre. True
E. Give one word answer.
1. A substance having a single unit structure. 1. monomer
2. A substance with numerous units joined together. 2. polymer
3. Process of monomers joining together to form a polymer. 3.
Polymerization
4. A natural monomer. 4. Glucose
5. A natural polymer of glucose. 5. Sucrose
6. A plastic which does not stick while cooking. 6. Teflon
7. Plastic which is a poor conductor of heat and used for making handles
of cooking utensils. 7. Bakelite (Thermoset)
8. Plastic which resists fire and used for coating firemen's uniform. 8.
Melamine
9. A synthetic fabric which is suitable for summer wear. 9. Acrylic
10. Plastic used to spray on wood for protection from sun and rain and
give a shine to it. 10. Polyurethane
11. Name a fibre which is more of cellulose and less of plastic. 11.
Rayon
science mission class 8 solutions chapter 3 Synthetic Fibres and Plastics Part-02
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