Bakelite® molding compounds are formulated from one of four heat-cured, crosslinkable resin Melamine and Bakelite are thermosetting plastics. (a) The odd one is teflon. All Active Science Solutions for class Class 8 Science are prepared by experts and are 100% accurate. (b) Blended fabrics contain only synthetic fibres. (c) they can be repeatedly remoulded into desired shapes Polythene, polystyrene, PVC, melamine and formica are plastics. (b) Hydrogen chloride gas is given off when PVC is burnt. (c) silicon, sodium carbonate, calcium carbonate Thermoplastic is a type of a polymer which can be easily melted by providing heat in order to recycle the material. (b) terylene Thermoplastic polymers These are the linear or slightly branched long chain molecules capable of repeatedly softening on heating and hardening on cooling. The correct statement should be: (b) terylene What are thermosetting plastics? Polycot, a blended fibre is made from Phenol Formaldehyde Resin F2143-3 is produced by condensing a molar excess of phenol to formaldehyde in the presence of an acid catalyst. (c) Polymers are large molecules made by joining many small molecules. (d) True Bakelite is a very poor conductor of heat and electricity and it is used for making electrical switches. Dusters made of cotton (natural fibre) are good for use in kitchen. Ans: Two uses of Bakelite is. The material similar to silk in appearance is (a) Nylon (b) Rayon (c) Polyester (d) Terylene. Melamine is a thermoseting plastic which is resistant to fire and can tolerate heat better than other plastics. The word polymer is coined from two Greek words poly means many and mer means unit. (a) the process by which glass is cooled and made tougher Choose the thermoplastic and thermosetting plastic from the following: Melamine, PVC, polythene, nylon, Bakelite. Three properties of synthetic fabrics are as follows: (a) The odd one is teflon. (a) Annealing is the process by which glass is cooled and made tougher. polymer, blended fibre. (e) False (c) nylon The correct statement should be: Polymers are large molecules formed by the linkage of smaller molecules called monomers. Bakelite is a man-made (synthetic) material while Melamine occurs naturally (is organic). We provide a total manufacturing solution that covers planning, molding, decorating and processing. Thermosetting Plastic: Some plastics do not get deformed on heating, and cannot be re-molded into a new shape. As plugs and sockets may get heated up while they are being used, Bakelite, a thermosetting plastic, is used for making them. They absorb water and do not catch fire easily. When plastics are burnt, they release hydrogen chloride gas. Explain the difference between thermoplastics and thermosetting plastics. Ans: Thermosetting plastics are kind of plastic which once moulded cannot moulded again by heating. It is usually elastic and soft. Acrylic is a synthetic fibre, which is light, soft and warm. 2. Students are advised to practice the NCERT MCQ Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Pdf free download is available here. Rayon, which is obtained from cellulose, is a synthetic fibre. It is a thermoplastic, while bakelite, melamine and formica are thermosetting plastics. Thermoplastic type material can be recycled and reusable, while the runner or material waste for thermosetting plastic type cannot. (b) acrylic Nylon, rayon, acrylic, terene and polycot are synthetic fibres. It is used to make floor tiles, kitchenware and fire resistant fabrics. Explanation: Thermosetting plastics when moulded once can not be softened by heating. Without any doubt, that quality as well makes melamine a perfect material for decorative objects. They absorb very less water. Plastic is a very generalized term for polymers that can mean either a thermosetting or a thermoplastic Plastic. Are these statements true or false? Explain why, thermoplastics become soft on heating but thermosetting plastics do not become soft on heating. (a) dacron Blended fibres are fibres that are obtained by blending natural fibres with synthetic fibres. Choose the thermoplastics and thermosetting plastics from the following: Melamine, Polythene, Bakelite, Polyvinyl chloride. (a) they are light (a) synthetic fibres and plastics. 39) Write two uses of Bakelite ? (b) gas given off when PVC is burnt (b) False They are produced by the combination of synthetic fibres and natural fibres. These new plastics could be used to produce household products in … Even if they catch fire, they do not stick to the body of the person who is holding it. (c) Bakelite is used to make plugs and sockets. 40) State two uses of melamine ? (c) False (c) they do not conduct heat or electricity Bakelite is used for making electrical switches whereas melamine is used for floor tiles. Give scientific reasons for the following: (b) Thermoplastics are not used for making saucepan handles. (a) sand, sodium bicarbonate, limestone Our products include breaker parts, precision molded parts, high design requirements and precision automotive parts, as well as high-function products using our own in-house resin. Henry Ford made his own deadly version of Bakelite by mixing phenol, formaldehyde and defatted soybean meal which reacted to create a thermoplastic resin that could be molded under pressure to create durable nonstructural plastic parts, such as radio knobs, light switch pulls, distributor caps, body trim, etc. Sort out these fabrics into different groups: rayon, nylon, jute, acrylic, terylene, wool, silk, polyester, terry cotton, cotton. (d) polyester and cotton. (b) The odd one is polycot. Bakelite is a thermosetting plastic which is a poor conductor of heat and electricity. Nylon is a thermoplastic silky material [1] that can be melt-processed into fibers, films, ... Bakelite, Melamine, polycarbonates, polyurethanes, epoxies. (c) The odd one is acrylic. Which of the two is a thermosetting plastic: PVC or bakelite? Usually, the material is thermoplastic type if the product material is plastic; the material is thermosetting type if the product is Bakelite and melamine. As the containers used for microwave cooking should be able to sustain reheating without causing any damage to the food kept in them, these containers can be made of thermosetting plastics. (a) Polymers are small molecules made by stringing together several monomers. Bakelite® molding compounds are engineering thermosets (ETS) not engineering thermoplastics (ETP). (d) substances that are easy to mould and can regain their shape High quality cp9000 Thermoplastic Resin Powder , Phenol Formaldehyde Novolac For Composite Material from China, China's leading Phenol Formaldehyde Resin product market, With strict quality control Phenol Formaldehyde Resin factories, Producing high quality cp9000 Thermoplastic Resin Powder , Phenol Formaldehyde Novolac For Composite Material products. They can be moulded into different shapes again and again. (c) man-made materials and plastics. 5. (b) It is obtained from wood containing large amount of cellulose. View NCERT Solutions for all chapters of Class 8, FREE Downloadable NCERT Solutions.Works without internet. It is a synthetic fibre, while cotton, jute and silk are natural fibres. The formation process of these two types of plastics also differs. (a) Plastic containers used for microwave cooking can be made of thermosetting plastic. Fuji Bakelite is a plastics manufacturer that offers a balance of technology and art. It is a thermoplastic, while bakelite, melamine and formica are thermosetting plastics. Which of the following correctly lists the raw materials needed to make glass? As wood contains huge amount of cellulose, rayon (synthetic fibre) is prepared chemically from wood pulp (cellulose). (a) melamine  (d) synthetic fibres and thermoplastics. In the growing consumer market of the 1930s and after, Bakelite faced competition from other thermosetting resins such as urea formaldehyde and melamine formaldehyde and from new thermoplastic resins such as cellulose acetate, polyvinyl chloride, polymethyl methacrylate, and polystyrene. Polythene and poly vinyl chloride are thermoplastics. Three properties of synthetic fabrics are as follows: (a) Melamine (b) Polythene (c) PVC (d) Nylon. (c) they do not conduct heat or electricity (d) cotton, jute, silk, rayon These solutions for Man Made Materials are extremely popular among Class 8 students for Science Man Made Materials Solutions come handy for quickly completing your homework and preparing for exams. Rayon is prepared chemically from wood pulp (cellulose). Soln: Answer is (a) Melamine. They cannot be moulded more than once as they take a firm shape once they are heated and cooled. (d) sand, sodium carbonate, calcium carbonate. They are also insulators of heat and electricity. Plastics are used to cover electrical cables because _____________. (b) acrylic (c) Dusters made of nylon or other synthetic materials are good for use in the kitchen. This results in environmental pollution. This is the key to their strength, toughness and durability. They absorb less water and they dry easily. Check the below NCERT MCQ Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Pdf free download. The list of materials mentioned above can be classified as (b) they become hard after heating It is a polymer (synthetic fibre) made up of small chemical molecules called esters. (b) The odd one is polycot. (c) polythene (e) The odd one is ester. We can sort the given fabrics into natural, synthetic and blended fibres as shown in the table below: Find the odd one out in the following. for example : Bakellite , melanin, Formaldehyde Thermoplastic Plastic are kind of plastic which can be moulded again and again by heating and easily reused.For example :PVS, Polysterine , nylon , polythine polythene, polystyrene, nylon, PVC, rayon, terene, acrylic, formica, polycot, melamine Such plastics are called thermosetting plastic. 3- Bakelite is a synthetic plastic and Melamine is … Thermoplastic is used for making combs, toys, buckets, mugs, etc. (a) polyester and nylon. The correct statement should be: This hydrogen chloride gas gets combined with the moisture in the environment to form hydrochloric acid, which is toxic and can cause problems to the human body. ​Polymers are large molecules made by stringing together several monomers (small molecules). These fibres have mixed properties of both the fibres involved in its production. The decorative melamine board has a structure obtained by laminating a surface layer and a core layer. It is because of these advantages of polyester over cotton that polyester is blended with cotton to form polycot. (f) False These polymers possess intermolecular forces of attraction intermediate between elastomers and fibres. Some examples are bakelite, melamine, formica, etc. (b) It is obtained from wood containing large amount of cellulose. Types of Polymerisation 1. (b) silicon, sodium bicarbonate, limestone (c) large molecules made by joining many small molecules together (d) they can coloured by adding pigments. Rewrite the false ones correctly. Thermoplastic: Plastics that can be deformed easily upon heating and can be bent easily. (c) cashmere Which of the following statements is true for rayon? (a) Annealing is the process by which glass is cooled and made tougher. Kerala Plus Two Chemistry Notes Chapter 15 Polymers. It is a monomer (small molecule) unit, while polyester, cotton and nylon are polymers (larger molecules made up of smaller monomer units). Bakelite, or polyoxybenzylmethyleneglycolanhydride, is an early plastic. Some examples are polythene, polyvinyl chloride (PVC), polystyrene, teflon, etc. Bakelite is a thermosetting plastic, it cannot be molded again whereas Melamine, being a thermoplastic, can be molded any number of times adn reshaped. The plastics which when moulded once, cannot be softened by heating are called thermosetting plastics. They are produced by the combination of. Soln: Answer is (b) Rayon. 3. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students. Sand (silicon dioxide (SiO2), sodium carbonate (Na2CO3) and calcium carbonate (CaCO3) are the three raw materials needed to make glass. Like bakelite and Perspex, the objects made of melamine can have polished and shiny surfaces which can be achieved by molding or treating objects with very fine abrasives. Plastics are bad conductors of heat and electricity (good insulators). It is used to make electrical switches and handles of utensils. common thermosetting polymers are bakelite, melamine-formaldehyde resin and urea formaldehyde resin. ended fabrics contain both synthetic and natural fibres. They become soft only the first time; they become hard. Which of the following is a polyester fibre? 3. (d) polyester and cotton source:www.intercosmo.net ; Thermoplastics: The plastic which becomes soft on heating and can be remolded into desired shape is called thermoplastic. (a) rayon synthetic fibers and plastics; class-8; Share It On Facebook Twitter Email. It is not a polyester synthetic fibre, while dacron, terene and terylene are polyester synthetic fibres that are manufactured from petroleum products. (d) acrylic. Chain Growth Polymerisation or Addition Polymerisation It involves formation of reactive intermediate such as free radical, a carbocation or a carbanion. They are not infected by bacteria or fungus and are resistant to insects. (d) All the statements are correct. (a) Thermosetting plastics remain hard on reheating and can sustain high temperatures. These are used in the manufacturing of toys, combs and different types of containers. Linear polymers and a combination of linear and cross-linked polymers come under thermoplastics. (b) they become hard after heating (d) Polyester fibres are obtained from petroleum products. The plastics which gets deformed easily on heating and can be bent easily are called thermoplastics. For example, polythene and PVC are thermoplastics. At home, when she burnt a small piece of fibre from the sweater, it smelled like burning plastic. Name the following: Explanation: For example, polycot is obtained by blending cotton with polyester. 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Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. For example, Bakelite is a thermosetting plastic which is a poor conductor of heat and electricity. It is a thermoplastic, while bakelite, melamine and formica are thermosetting plastics. (f) two fabrics made from petroleum products. (b) teflon All questions and answers from the Active Science Book of Class 8 Science Chapter 3 are provided here for you for free. In 1927 the Bakelite patent expired. 1 Answer +1 vote . (d) polyester. We have provided Synthetic Fibres and Plastics Class 8 Science MCQs Questions with Answers to help students understand the concept very well. Is it thermoplastic or thermosetting plastic ? (d) sand, sodium carbonate, calcium carbonate Blended fabrics contain both synthetic and natural fibres. Synthetic condensation polymers have a wide array of household, industrial, commercial, and medical uses … Anu bought a sweater which was not very expensive. Acrylic is a synthetic fibre that can be used instead of wool. Give two examples of thermosetting plastics. Melamine is a thermosetting plastic which is resistant to fire and can tolerate heat better than other plastics. Therefore, thermoplastics are not used for making saucepan handles. (d) they become soft again and again on reheating. Examples are bakelite and melamine. Thermoset are useful in high temperature applications since they do not soften like a thermoplastic. Polythene and PVC are examples of thermoplastic. Bakelite & Melamine Injection Molding Machine, Model: LCH-H80 toLCH-H500 ; LCH-V100 to LCH-V850, There are two types of injection features: the thermoplastic type and thermosetting plastic type. Making electric fittings such as electric switches, Making plugs and sockets. 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