In the 1930s cast Bakelite, along with many other competing phenolic resins, enjoyed a vogue in colourful costume jewelry and novelties. We should not throw polythene bags, wrappers of chips, biscuits and other eatables in water bodies, on the roads, or picnic spots. Ans: we should buy cotton shirts for summer. That’s why synthetic fibres are become so popular. 3.– rubber — is used in conveyor belts. Ankit was learning how to cook. 51) Ans: Rayon is a man-made fibre prepared from a natural raw materials (called cellulose) by chemical treatment. Ans: PET is a very popular form of polyester. 16) What is a polymer ? for making a number of medical instruments. Name the natural polymer of which cotton is made ? Rayon is used in medical field for making bandages and surgical dressings. (i) These plastics can be moulded and reset a number of times. Uses of Bakelite. Bakelite® was widely used in the 1920s and 1930s in the United States and Great Britain. (b) The properties and uses of polystyrene are as follows:Properties: 1) It can be easily moulded.2) It has poor chemical resistance. 2) It does not react chemically with other substances. It is used for making electric switches,plugs and sockets because 2)It does not become soft on getting heated. 31) Explain why, frying pan handles are made of thermosetting plastics ? Chapter 1. 5. All Plastics have one common property what is it? But we wear many dresses which are not made from silk, but they appear to resemble silk. Polythene – making polythene bags, bottles etc. 3> uses are: making electric switches, floor tiles, ballpoint pens etc. Why do we use melamine for making kitchenware? Cords of electrical appliances and cables also have plastic coating.b) Plastics are insoluble in water and that is why we use plastic buckets to store water and use plastic glasses to drink water.c) Plastics are inert to air and water. Ans: The uses of polyester are as follows:(a) Polyester is used to make pants, shirts, suits and bed sheets because it is strong and crease resistant. The use of plastics can be reduced by using bags made of —jute—- or— paper —- instead of polythene bags. Phenolic resins are also extensively used as adhesives … All Plastics have one common property that they are made up of polymers. (ii) Take a cotton carry-bag or a jute bag while going for shopping. Multiple Choice Questions Question. Hence, they are used to make things such as toys, buckets etc. (c) Bakelite is used for making handles of frying pans. We should try to reduce the use of plastics by using other materials in their place. A synthetic fibre classified as polyester (8) 7. 1)It is a poor conductor of heat. Can you write the major difference between these two types of plastics? Fibres possess high tensile strength because the chains possess strong intermolecular forces such as hydrogen bonding. Also after the chapter you can get links to Class 8 Science Notes, NCERT Solutions, Important Question, Practice Papers, etc. → It is widely used in various industries and for making a variety of household articles. It is a thermosetting polymer and Bakelite has high strength meaning it basically retains its form even after extensive molding. Ans: Synthetic fibres catch fire very easily. Ans. Jewelry. Prystal was a trade name used for a type of transparent Bakelite marketed by the American Catalin Corporation in a number of different colors. Burning cotton smells like burning paper, whereas burning wool smells like burning hair. Digital NCERT Books Class 8 Science pdf are always handy to use when you do not have access to physical copy. 2> they are less expensive. Can you write the major difference between these two types of plastics? The two example of biodegradable materials are: Animal wastes and paper. Ans: Any material which can be melded into any desirable shape on heating is called plastic. 54) Thermopalstics can be softened by heat but thermosetting plastics cannot be softened by heat. Even though it was technically made of Catalin, most collectors still reference it as a type of Bakelite. 1. State the uses of PET ? 25) Why should we not wear clothes made of synthetic fibres (like nylon or polyester) while working on the kitchen ? 3> they are readily available and easy to maintain. Uses: It is used to make electrical goods, combs, fountain pens, buttons, plugs and switches. Substance used as synthetic wool (7) 2. MySqlBulkLoader Class: Allows importing large amounts of data into a database with bulk loading. Due to its excellent insulating properties it is used for making switches and other electrical appliances. NCERT Exemplar Class 8 Science Unit 3 Synthetic Fibres and Plastics. Question 1.Electrical switches are made of(a) nylon(b) bakelite(c) polythene(d) melamineAnswer:(b), Question 2.Out of the following, which is not biodegradable ? MySqlBulkLoader Properties. A synthetic fibre classified as polyester (8) 7. Name the popular polyester ? Nylon is used in making ropes, car seat belts, fishing nets, tyre cord, strings for sports rackets and musical instruments. It was crafted into rotary-dial telephones, radios, electric guitars, appliance parts, door knobs, bangles, and more. They are inflammable. It is used for making electrical switches, electric plugs and plug boards, etc. Bakelite is a thermoset plastic, meaning that its polymer chains are hooked together through the heat and pressure applied when it is molded. It played a large role in bringing electronics into the automobile industry because it is heat and electricity resistant. The molecules set the way batter sets in a … Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Nylon is used for making textiles like sarees, shirts, neck-ties, tights, socks, and other garments. If you have one of these and want to bring back the shine on it, go through the Bakelite cleaning tips highlighted in this HomeQuicks article. It is used for making gaskets, pump packings, valves, seals etc. Required fields are marked *. NCERT Exemplar for Class 8 Science Chapter 3 Synthetic Fibres and Plastics 7. Another name for this compound is artificial silk (5) Down 5. They are used for making cabinets of radio, television, telephone sets, water tanks, water pipes, electric switches, cups plates, dinner sets, etc. 8. We should not throw polythene bags,  wrappers of chips, biscuits and other eatables in water bodies, on the roads, or picnic spots. Materials : Metals And Non-Non Metals Chapter 4 Solution, Conservation Of Plants And Animals Chapter 7 Solution, Cell Structure And Functions Chapter 8 Solution, Reproduction In Animals Chapter 9 Solution, Reaching The Age Of Adolescene Chapter 10 Solution, Chemical Effects Of Electric Current Chapter 14 Solution, Some Natural Phenomena Chapter 15 Solution, Stars And The Solar System Chapter 17 Solution, Pollution Of Air And Water Chapter 18 Solution, It was so useful for our study and I want to say thank’s the coder or inventer of this website, Your email address will not be published. Check the below NCERT MCQ Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Pdf free download. 3. 4> they dry up quickly and are wrinkle resistant. Give two important uses of nylon. Our pots use genuine Bakelite handles to last the generations). Substance made up of large number of smaller molecules (7) 4. 1) Name the units of which cellulose polymer is made ? 3. PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. 3. A type of fibre obtained naturally from cocoon (4) 6. 4) Name the fibre obtained by the chemical treatment of wood pulp (or cellulose).  Making bandages, syringe and some another surgical dressings. Its fibres can also be woven like those of natural fibres. Thermoplastics : polythene and polyvinyl chloride, Thermosetting plastics : melamine and Bekalite. Nylon fibres are very strong, fairly elastic. Nylon is used in making curtains, sleeping bags and tents. 2) It is harder than other plastics. It is used for making saucepan handles. For example : Cotton, Jute. Here we give Chapter 3 all solution of Class 8. Answer – Saucepan handles are made of thermosetting plastics because thermosetting plastics are poor conductor of heat. 2. 3. They are non reactive and do not corrode easily. Bakelite:It is a very hard and tough plastic.It is a poor conductor of heat and electricity. Ans: Clothes purely made of synthetic fibres are not comfortable to wear so they are mixed with natural fibres. c) Acrilon is pure wool obtained from sheep. Class 8 Science Chapter 3 MCQ with complete explanation are given below. Why then is there concern today about their increasing use. A polymer used … Bakelite was used to manufacture everything from telephone handsets and costume jewelry to bases and sockets for lights bulbs to automobile engine parts and washing machine components. NCERT Solutions Class 10 Science (Physics,Chemistry, Biology). Principle in the context of use of plastics ? Give two reasons only. 9. Ans: Polyester is a type of synthetic fibre. 36) choose the thermoplastics and thermosetting plastic from the following: 38) Write the full form of PVC ?  Is it thermoplastic or thermosetting plastic ? It is also used for making floor tiles, kitchenware, in aeroplanes and buses to prevent the spread of fire. 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