Question: Explain why plastic containers are favored for storing food.Â. Answer: A plastic which cannot be bent or reshaped is called thermosetting plastic. 5. Give an example of a biodegradable aliphatic polyester. Polymers are made up of small units called _____,           (a) layers                                 (b) molecules,           (c) cells                                   (d) monomers, 04. What is the name of plastic that is used in making non stick pans? Synthetic fibers are not good absorbers of _______ .Â, c. In______ weather clothes made of synthetic fiber stick to the body.Â, d. Synthetic fibers catch fire easily so they are _______ .Â, e. Clothes made of synthetic fibers should not be worn in ______, a. Examples of thermosetting plastics include bakelite, urea-formaldehyde resins. Natural fibres: These are obtained from natural sources, called natural resources. This is helpful in the manufacturing of mats or carpets that are used at home for decoration. It is rough and tough type of fiber. What is a biodegradable polymer? By this method, we will observe the water absorbing tendency of fiber. Parachutes and ropes for rock climbing which indicates that nylon fibres are strong. Why has government banned the use of polythene bags ?Â, Polythenes or plastic bags are non biodegradable. Synthetic Fibres and Plastics Class 8 Science Chapter 3 as per NCERT Book used in CBSE and other Schools.           (a) Nylon                                 (b) Rayon,           (c) Acrylic                               (d) Polyester. Sea is the greatest source of some halogens. Bakelite: Bakelite is phenol formaldehyde resin with monomer chemical formula of (C 6-H 6-O.C-H 2-O). What is the name of first fully synthetic fiber? There are two types of plastics which are written below: Thermoplastic is a plastic which gets deformed easily on heating and can be bent easily. Question: Fill in the blanks with correct word- It is hydrophobic in nature and dries up quickly as it does not absorb water. Bakelite is used for making electrical switches, handles of various utensils etc. Comment. mountaineers use nylon ropes for climbing the mountains because. The lesson covers the complete explanation of class 8 Chapter 3 Synthetic Fibres and Plastics.Topics covered are Introduction to fibres, kinds of fibres. Question 12 Why thermosetting plastic does not become soft on heating? 2. 13. It has ability to be lustrous, semi lustrous or non lustrous. 1)Thermoplastic.          (a) nylon                                  (b) rayon Answer: Teflon Plastic is also defined as a material that can be heated and molded in any shape after cooling. These plastics cannot be softened again on heating. Thermoplastic polymers are linear (slightly branched) long chain polymers, which can be repeatedly softened and hardened on heating. The polymers in which smaller units are linked to each other in. Which of the following is a natural fiber? When you are studying polymers in chemistry you will generally come across a typical question like “distinguish between or write the differences between thermoplastic and thermosetting plastic.” While thermoset plastics and thermoplastics sound very similar, they are totally different compounds and have different properties as well as applications. For example: Plastics. e. ______ is called a regenerated fiber.Â. These are generally used in adhesives. Discuss the main purpose of vulcanisation of rubber. Give examples which indicate that nylon fibres are very strong. The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. If the cloth catches fire it can be very disastrous. Different types of synthetic fibres like, Rayon fibres, Nylon fibres, Polyester fibres and Acrylic fibres have been explained. The lesson covers all important questions based on Synthetic Fibres and Plastics. Name the basic component of animal fibres. Some monomers of plastics have proven to cause cancer also. If in case you are unable to identify the fiber, you can take help of your parents in selecting these pieces. The properties of synthetic fibres are as follows-. Is ( NH — CHR — CO )n a homopolymer or copolymer? Electric wires are coated with—PVC——. Synthetic fibers have a wide range of use ranging from household articles like ropes, buckets, furniture, containers, etc. Polyester is manufactured from petroleum. Download CBSE Class 8 Science Synthetic Fibres and Plastics MCQs in pdf, Science chapter wise Multiple Choice Questions free, Chapter 3Synthetic Fibres and Plastics 1 A chain of small chemical units combined to form a large single unit is called ____a) Polymerb) Polyc) Polythene 1.          (c) fibre                                  (d) elastomer, 08. These cheap garments are made up of rayon. 15 Qs. Definition of Thermosetting Plastic. Question: What is the chemical nature of polyester? NCERT Books; thermosetting plastic. Question: Give examples which indicate that nylon fibers are very strong.          (c) Wood                             (d) Plastic, 15. There are certain fibers which are obtained from plants and are known as vegetable fibers. Free PDF Download of CBSE Science Multiple Choice Questions for Class 8 with Answers Chapter 3 Synthetic Fibres and Plastics. For example: Viscose comes from pine trees.          (c) synthetic fibre                  (d) both (a) and (c), 09. Which term is used for polymers made up of a large number of glucose units? It is highly resistant to insects, fungi, animals, chemicals, etc. If the density of solution is 1.2 g mL-1, then what shall be the molarity of the solution? This allows the chair to remain in one shape only without getting affected by sun heat. Answer: Nylon, terylene, PET, acrylic, teflon, etc. Which term is used for polymers made up of a large number of glucose units? Due to this property, it is used for making fishing nets, parachute, bag, ropes etc. Topics covered are Introduction to fibres, kinds of fibres. Name some artificial fibres. It is used for making bottles, utensils, films, wires and many other useful products. Answer: Rayon Your No1 source for Latest Entrance Exams, Admission info, January 8, 2019 by SuccessCDs Team in CBSE Class 8 Science Lessons Explanation, Notes, NCERT Question Answers. 13.   Esters are the chemicals which give characteristics smell like fruits. k.setAttribute("data-push", "1"); Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution. Teflon is used in making non stick pans because oil and water does not stick on it. Answer: Poly vinyl Chloride          (a) jute                                  (b) rayon 1. (i) poor conductors of electricity Give an example of natural polymer? In this chapter we will discuss about fibers and plastics in detail. Name any two types of polyesters and their uses.Â, Answer: Fabric made from polyester does not get wrinkled easily. Natural fibers are obtained from plant and animal sources. (v) Zinc amalgam and dilute hydrochloric acid. What are polycot and polywool? Synthetic fibers are not good absorbers of _______ .  What are natural and synthetic polymers? 1.          (a) plastic                                (b) wool ______ fibers are less expensive than natural fibers.Â, b. Also find the composition of the vapour phase. Acrylic fiber is often used for making sweaters, blankets, cashmere, jackets, shawls, and tracksuits. PET (Polyethylene terephthalate), the commonly used polyester, is made from two monomers by condensation polymerization.           (c) Nylon                                 (d) Cotton, 03. ______ burns slowly with the smell of burning hair.           (c) jute                                    (d) rayo, 06. —–synthetic——-fibre on burning, smells like burning paper.          (a) Toys                                 (b) Cooker handles,          (c) Carry bags                       (d) Plastic chair, 11. Polycot is a mixture of polyester and cotton. 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