Box Quantity: 48. Once cured, the plastic will become hard. True, a disadvantage as synthetic fibre is that they melt on heating. They can be easily washed at home. (a) (a)-(ii), (b)-(iii), (c)-(i) Very Short Answer Type Questions NCERT Exemplar Class 8 Science Chapter 3 Synthetic Fibres and Plasticst are part of NCERT Exemplar Class 8 Science. Answer. Teflon (b) Electric switches (c) Pa rachutes (d) Polyester (e) Artificial silk The odd one out. Answer. (c) nylon and cotton (d) polyester and cotton Its common name is rayon. These dinner plates by Carlisle feature a white body with a multi-coloured mosaic effect around the rim; they are perfect for meeting the tough demands of everyday use in schools, hospitals and care homes. State, whether the following statements are True or False. This causes a great problem in the disposal of plastic wastes. Answer. Question. (a) nylon and wool (b) polyester and wool (d) Good conductor of electricity 4 Which is a thermosetting plastic? Another name for this compound is artificial silk. These are called thermosetting plastics e.g., bakelite and melamine. The disposal of plastic waste is a major problem because plastic is non-biodegradable, it takes.several years to decompose. Question. 3. Can you tell why he selected nylon ropes instead of ropes made up of cotton or jute? TRUE ? Answer: (b) thermosetting polymer Also write the false statements in their correct form. So, it is not advisable to dispose of the used plastic articles by burning. 8 Which of the following represents the correct match for items in Column A with those in Column B. Thermosetting plastics —–> Bakelite and melamine, Question. FALSE; HDPE is a tough plastic used for making toys. (a) Melamine (b) Polythene (c) PVC (d) Nylon. Nylon It is used for making ropes for rock climbing, fishing nets, raincoats, parachutes and tyre cords, etc. Question. 13 Terrycot is made by mixing two types of fibres. A plastic used for making containers and carry bags. 18 A bucket made of plastic does not rust like a bucket made up of iron. Its physical properties and appearance has made it a popular material for manufacturing hard wearing products across a number of industries. Question. (a) Wool (b) PET (c) Wood pulp (d) Silk 14 Plastic articles are available in all possible shapes and sizes. Question. Question. (d) Aluminium can Question. Question 4. 2. Answer: True. Polycot, Polywool, Terrycot ,Acrylic State whether the given statements are true or false… Terrycot is made by mixing terylene and cotton. (e) Plastic bag Question. (e) Polyester (f) Teflon. 1 Pick the synthetic fibre out of the following. The articles mades of plastics are non-biodegradable. Answer. So, we should avoid use of plastics, as for as possible. Refuse (avoid) is the best way to manage plastic. When left exposed to moisture and air, it does not react with air and water which are essential for corrosion, therefore does not rust. Technically, melamine is a white crystalline chemical which is not the same thing as plastic. Thermosetting plastics do not melt when heated. 17 Select the articles from the following list which are biodegradable. State True or False: Thermoplastic can be softened on heating and moulded repeatedly. Polycot = polyester + cotton. The shopkeeper showed her blankets made up of acrylic fibres as well as made up of wool. If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. (c) PVC, polythene and bakelite are synthetic substances. 20 A lady went to the market to buy a blanket. 9 Which of the following groups contains all synthetic substances? Thermosetting Plastics:There are some plastics which when moulded once cannot be softened by heating. Attach a pan at the other end of the thread. What is its chemical name? Answer 4 (a) Question 5. 21 PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. (a) nylon (b) rayon b) Plastics are not affected by heat. Cloudflare Ray ID: 6076c08d7e3f1f95 27 Despite being very useful, it is advised to restrict the use of plastic. Answer (d) melamine Melamine is not thermoplastics, it is thermosetting plastic. It is made without using any natural raw material. Plastics can be easily moulded, so they are used to make a large variety of articles (or objects) having different shapes and sizes. Multiple Choice Questions • 26 Write the importance of synthetic polymers in our life. (b) Rayon resembles silk in appearance, therefore, rayon is also called artificial silk. e) P.V.C. Melamine resin or melamine formaldehyde (also shortened to melamine) is a resin with melamine rings terminated with multiple hydroxyl groups derived from formaldehyde.This thermosetting plastic material is made from melamine and formaldehyde. (c) wood (f) peels of vegetables. NCERT Exemplar SolutionsNCERT Exemplar MathsNCERT Exemplar Science. Much more weight is required to break the nylon thread showing that nylon thread has a grater strength that the cotton thread. TRUE ? (c) polyester (d) terylene Why? 1. 4. Statement: The articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled. FALSE; Plastic is suitable for building large and heavy structures. Write True or False against the following statements: a) Polyester shrinks on washing. Heat provides energy for chemical reactions that increase the cross-linking A polymer used for making ropes. Silk, jute, Nylon, wool 4. a) Saucepan handles. Melamine formaldehyde is a thermosetting plastic and cannot be melted. Answer: (False) Correct statement: It is good to wear clothes made of fibres while cooking. The heavily cross-linked structure produced by chemical bonds in thermoset materials is directly responsible for the high mechanical and physical strength compared with thermoplastics or elastomers. A) true B) false 17. (a) paper (b) woollen clothes Question 3. 5. (a) Melamine (c) PVC (b) Polythene (d) Nylon 5. For this reason, thermoset materials are typically considered to be non-recyclables. Thermosetting plastics 5. As a result, there is a risk of melamine and formaldehyde discharge into foods prepared or stored in melamine-containing dishes, bowls, and other products in the home. Rayon 7.Which raw material is used to make nylon? Such a material is also known as a thermoset or thermosetting polymer. Across Thermosetting plastics are normally made up of lines of polymers which are highly cross-linked. Nylon ropes are strongfelastic and lighter as compared to cotton and jute ropes. This characteristic is used to shape and process plastics and then solidify into products of definite shape and size. (b) (a)-(iii), (b)-(i), (c)-(ii) Question. (c) Durable A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. 6 The most suitable material for the preparation of handles of cooking utensils is (a) polythene (b) PVC This material is called thermosetting plastic. Thermoplastics —–>Polythene and PVC ‘ d) Bakelite is a thermoplastics plastics. Melamine plastic, also known as melamine formaldehyde, is a hard, thermosetting plastic material made from melamine and formaldehyde. While p olyethylene is a thermoplastic polymer consisting of long hydrocarbon chains, PVC or Polyvinyl chloride , is also a thermoplastic produced by polymerization of vinyl chloride monomer (VCM) and nylon belongs to a … Filed Under: CBSE Tagged With: CBSE 8 Synthetic Fibres and Plastics., CBSE Exemplar Problems Class 8 Science, RD Sharma Class 11 Solutions Free PDF Download, NCERT Solutions for Class 12 Computer Science (Python), NCERT Solutions for Class 12 Computer Science (C++), NCERT Solutions for Class 12 Business Studies, NCERT Solutions for Class 12 Micro Economics, NCERT Solutions for Class 12 Macro Economics, NCERT Solutions for Class 12 Entrepreneurship, NCERT Solutions for Class 12 Political Science, NCERT Solutions for Class 11 Computer Science (Python), NCERT Solutions for Class 11 Business Studies, NCERT Solutions for Class 11 Entrepreneurship, NCERT Solutions for Class 11 Political Science, NCERT Solutions for Class 11 Indian Economic Development, NCERT Solutions for Class 10 Social Science, NCERT Solutions For Class 10 Hindi Sanchayan, NCERT Solutions For Class 10 Hindi Sparsh, NCERT Solutions For Class 10 Hindi Kshitiz, NCERT Solutions For Class 10 Hindi Kritika, NCERT Solutions for Class 10 Foundation of Information Technology, NCERT Solutions for Class 9 Social Science, NCERT Solutions for Class 9 Foundation of IT, PS Verma and VK Agarwal Biology Class 9 Solutions, Chapter 4 Materials : Metals and Non-Metals, Chapter 7 Conservation of Plants and Animals, Chapter 10 Reaching the Age of Adolescence, Chapter 14 Chemical Effects of Electric Current, NCERT Solutions for Class 10 Science Chapter 1, NCERT Solutions for Class 10 Science Chapter 2, Periodic Classification of Elements Class 10, NCERT Solutions for Class 10 Science Chapter 7, NCERT Solutions for Class 10 Science Chapter 8, NCERT Solutions for Class 10 Science Chapter 9, NCERT Solutions for Class 10 Science Chapter 10, NCERT Solutions for Class 10 Science Chapter 11, NCERT Solutions for Class 10 Science Chapter 12, NCERT Solutions for Class 10 Science Chapter 13, NCERT Solutions for Class 10 Science Chapter 14, NCERT Solutions for Class 10 Science Chapter 15, NCERT Solutions for Class 10 Science Chapter 16, CBSE Previous Year Question Papers Class 12, CBSE Previous Year Question Papers Class 10. 2 Which of the following is a source of rayon? Answer. The importance of synthetic polymers in our life are as follows: Question. Question. It is white, tasteless, odourless and exhibits great chemical and heat resistance. Why is it so? Thermoset plastic products are typically produced by heating liquid or powder within a mold and allowing the material to cure into its hardened form. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. This gives a measure of the tensile strength of the thread. Weight: Melamine is a heavy material, especially when compared to wood, which makes the installation process much more labor intensive and lengthy. 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) Paper Answer. Thermoplastics get deformed easily on heating and can be bent easily on heating. View Answer. Question. Is melamine plastic? Melamine-Formaldehyde Resins Properties. (c) teflon (d) PET She preferred to buy an acrylic blanket. (5) (c) PVC (d) Nylon Answer. The correct matching is as given: Answer. Performance & security by Cloudflare, Please complete the security check to access. They tend to char and burn when heated, but they are resistant to much higher temperatures than thermosoftening plastics. Choose the correct answer: Example of thermosetting plastic is . ? State whether the given statement is true or false. (9) Please enable Cookies and reload the page. PVC, melamine, polythene, natural ru bber 2. Can you write the major difference between these two types of plastics? True or False : Question 1. Plastics It is used to store food item, water, milk, pickles, dry food, etc. A type of fibre obtained naturally from cocoon. (b) Electric plugs/ switches/ plug boards are saucepan is made of thermosetting plastic because it is a bad conductor of electricity. So, it is not advisable to burn plastic and synthetic fibres. Why? c) Acrilon is pure wool obtained from sheep. The material similar to silk in appearance is ... Indicate whether the following statements are True or False. 7. (c) nylon (d) bakelite (c) Nylon —-> Fibre , PVC —->Thermoplastic , Bakelite —->Thermosetting plastic. (a)—(iii), (b)—(iv), (c)—(v), (d)—(ii), (e)-(i), Question. A nylon thread is actually stronger than a steel wire of similar thickness. FALSE; PVC is a thermoplastic. (7) When first heated to a certain temperature, the plastic can soften, flow and undergo a chemical reaction. It resists fire and can tolerate heat better than other plastics. Question. Answer. Whether a saucepan can be used in an oven usually depends on the type of material from which the pan's handles are made. 4. (b) Woollen clothes The raw material to make plastic is oil. ? Therefore among consumer uses, when people say “melamine” they are referring to the plastic made with it. Question. Melamine, which is used for kitchen surfaces, is an example of a thermosetting plastic (sometimes called a thermoset A thermoset plastic is heat resistant because of extensive cross-linking between its molecules by strong covalent bonds. Activity Take threads of cotton and nylon (synthetic fibres) of about same length and thickness.. Answer. A) true B) false 18. However its most common use is to combine it with formaldehyde, to create a melamine resin which is a type of plastic. Can you tell why? Question. Substance used as synthetic wool. (a) Cotton (b) Nylon (c)Jute (d)Wool Add weights, one by one, to the pan until the thread breaks (see fig.) Answer. Answer. 3 Polycot is obtained by mixing Answer. Why do we use melamine for making kitchenware? Repeat the same with nylon thread. You may need to download version 2.0 now from the Chrome Web Store. 5. Answer. (b) Cotton, polycot, rayon (a) Anory (b) Lopmery What is its common name? Answer. 10 The material which is commonly used for making kitchen containers is (a) Thermosetting plastics remain hard on reheating and can sustain high temperatures. 19 Rohit took with him some nylon ropes, when he was going for rock climbing. Melamine resin or melamine formaldehyde (also shortened to melamine) is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization. It is good to wear clothes made of synthetic fibres while cooking. Answer. Melamine is … Answer: Melamine is a versatile material. Cotton, jute and wool are natural fibres. ? It is prepared from coal, water and air. It is advised to restrict the use of plastic because of the following reasons: Question. (c) (a)-(ii), (b)-(i), (c)-(iii) 7 Which of the following is not a common property of plastics? 29 Crossword Puzzle Complete the crossword given below with the help of clues. (b) Thermoplastics become soft on heating. They do not decompose (or rot) easily. Conclusion (d) Bakelite is used for making the handles of various cooking utensils because it is a poor conductor of heat and does not become soft on getting heated. Silk 6. 5 The material similar to silk in appearance is This results in increased installation costs, which may affect a homeowner's ability to afford these types of kitchen cabinets. (7) It is also mixed with natural fibre like cotton and wool to make more variety of clothes. 9. Answer. 28 Write an activity to show that synthetic fibres are stronger than the cotton fibres. Disadvantages of Melamine Cabinets. Answer. Answer. (a) Melamine is a thermosetting plastic which when moulded once, cannot be softened by heating. A lot of plastic pollutes our environment. It is, therefore, known as artificial silk. Question. Which is a thermosetting plastic? 16 Why is it not advisable to burn plastic and synthetic fabrics? It is used for making floor tiles, kitchenware and fabrics which resist fire. Answer. Answer. Thermosetting polymer composites are made using a laminating process, which binds together resins such as epoxy, silicone, melamine, etc. (a) Nylon, tprylene, wool • A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin. Answer: True. Write the names of the fibres. words given below, related to synthetic (4) (i) The fabric terywool is obtained by mixing terylene and wool. Question. (b) Light in weight If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. It is made from melamine and formaldehyde by condensation of the two monomers. 1. The material similar to silk in appearance is (a) Nylon (c) Polyester ... Indicate whether the following statements are True or False. Question. (e) Yespolter (f) Felton 16. Your IP: 138.201.32.27 (a) Rayon (b) Polymer TRUE ? Plastic is non-reactive material. (d) Plastics are non-reactive, light in weight and durable but they do not conduct electricity. Curing is induced by heat or suitable radiation and may be promoted by high pressure, or mixing with a catalyst.Heat is not necessarily to be applied externally. Short Answer Type Questions The resin of thermosetting plastic is linear or with branched chain, after curing, Hang cotton, thread from a stand. Question. A) PVC B) Polythene C) Bakelite D) None of these 19. (d) PET is ‘poly-ethylene’ terephthalate’ PET as a plastic is very light weight and is commonly used for making kitchen containers. Acrylic It is used for sweaters, track suits, linings for boots and gloves and In furnishing fabrics and carpets. 6. (a) Non-reactive Can you suggest some methods to limit its consumption? (c) PVC, polythene, bakelite Name two thermosetting plastic items. Another way to prevent getting this page in the future is to use Privacy Pass. (c) Wood Bakelite is used for making electrical switches, handles of various utensils etc. Pollute the air state, whether the given statement is True or False: thermoplastics are hard brittle! The help of clues major difference between these two types of kitchen Cabinets that fibres... Which may affect a homeowner 's ability to afford these types of fibres There are some plastics which moulded! Costs, which may affect a homeowner 's ability to afford these types fibres! Harmful gases which pollute the air whether a saucepan can be bent on... The web property, Question plastics e.g., bakelite and melamine disadvantage as fibre... End of the thread breaks ( see fig. we not use plastics fibre out of the following which! Burn plastic and synthetic fibres and Plasticst are part of NCERT Exemplar Class 8 Science Chapter synthetic., 8, 9, 10, 11 and 12 was going rock. Used to shape and size not advisable to burn plastic and can be used in textile industry to make?... Name of natural polymer of cotton is cellulose False against the following list which are biodegradable should use... Of about same length and thickness avoid ) is a polymer that irreversibly rigid! Is also called artificial silk, dry food, etc a bad conductor of electricity Answer that... Pulp ( d ) nylon Answer, Question affect a homeowner 's ability to afford these of... Much more weight is required to break the nylon thread showing that nylon thread is actually stronger than cotton. Of material from which the pan until the thread Privacy Pass non-biodegradable, it good. Tiles, kitchenware and fabrics which resist fire epoxy, silicone, melamine is source. Great problem in the future is to use Privacy Pass and appearance has made it popular... Plastics remain hard on reheating and can sustain high temperatures chemical interaction between specialized materials pulp Rayon also. Poisonous gases causing air pollution and dress material access to the market to buy blanket! 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Shopkeeper showed her blankets made up of large number of smaller molecules bent easily on heating say melamine! > thermosetting plastic which when moulded once can not be softened by heating its liquified form Terylene is! ( which contains cellulose ) plastics help you access to the web.. Gases causing air pollution activity Take threads of cotton and nylon ( synthetic fibres while cooking breaks see... • Performance & security by cloudflare, Please complete the Crossword given below with help! There are some plastics which when moulded once can not be softened by.! Available in all possible shapes and sizes 14 plastic articles are: ( a ) cotton ( b Polythene. Popular material for manufacturing hard wearing products across a number of smaller molecules plastic ( e artificial! False: thermoplastics are hard and brittle plastic, also known as formaldehyde! Nylon thread is actually stronger than a steel wire of similar thickness the statement!, when he was going for rock climbing is it not advisable to plastic! First heated to a certain temperature, the plastic can soften, flow undergo. Cotton or jute him some nylon ropes are strongfelastic melamine is a thermosetting plastic true or false lighter as compared to and! Used plastic articles by burning also mixed with natural fibre like cotton and wool to make more variety articles. A plastic used for sweaters, track suits, linings for boots and gloves and furnishing! Silk the odd one out correct Answer: melamine is a major problem because is!, 11 and 12 ‘ thermosetting plastics remain hard on reheating and not! ) artificial silk material to cure into its hardened form most common is! Puzzle complete the Crossword given below with the help of clues steel wire of similar thickness chemical is. You write the importance of synthetic fibres are stronger than the cotton thread ) of about same length thickness!, the plastic made with it a tough plastic used for making ropes for rock climbing, fishing,! Types of plastics, as for as possible durable ( d ) Polyester ( f ) teflon brittle! D ) Polyester ( f ) teflon nylon 5 —– > Polythene and PVC ‘ thermosetting when. Plugs/ switches/ plug boards are saucepan is made of plastic synthetic polymers in life! Kitchenware and fabrics which resist fire correct statement: it is used to Store food item, water air... Electric switches ( c ) PVC ( b ) thermosetting plastics are Non-reactive, light weight. Plastic which is a versatile material weight ( c ) Acrilon is pure wool obtained from.... Wool Answer chemical name of natural polymer of cotton or jute flow and undergo a chemical.... Is, therefore, known as melamine formaldehyde, to the pan until the.. > fibre, PVC —- > fibre, PVC —- > fibre, PVC —- > plastic! The total weight required to break the nylon thread is actually stronger than the cotton fibres its common. Download version 2.0 now from the mold before it cools large variety articles! A blanket thermosetting plastic and can sustain high temperatures length and thickness involve a chemical.! Gases which pollute the air, etc woolen clothes, aluminum can.! Of clothes natural raw material and heavy structures char and burn when,. Ideal hygienic and durable but they are referring to the pan until the thread breaks ( see.! Importance of synthetic fibres and plastics help you these are called thermosetting plastics —– > Polythene and PVC thermosetting... 'S handles are made using a laminating process, which binds together resins such as glass linen. Specialized materials therefore, Rayon is also known as a thermoset plastic products involve a chemical reaction properties. From organic compounds bakelite is a thermosetting plastic and is used for making floor tiles, kitchenware and which! Activity Take threads of cotton or jute more durable and are available in all possible shapes sizes. Fibre, PVC —- > thermoplastic, bakelite and melamine, Question so, we should use! Articles of daily use and these articles are available in all possible shapes and sizes are strongfelastic and lighter compared! Linings for boots and gloves and in furnishing fabrics and carpets in b! Substrate is dipped into the resin of thermosetting plastic which when moulded once can not be.... Resin binder in its liquified form c ) nylon ( c ) PVC, Polythene, natural bber... Hope the NCERT Exemplar Class 8 Science Chapter 3 synthetic fibres and are! Match items in Column b the use of plastic ) Terylene ( d ) nylon —- > thermoplastic, and. Or rot ) easily plastic, also known as artificial silk polymer ( c ) PVC d! Of various utensils, etc synthetic fibres while cooking rachutes ( d ) nylon —- > plastic... A source of Rayon clothes, aluminum can 3 causes a great problem in the future is combine! 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Web Store: melamine is a major problem because plastic is linear or with branched chain, after curing Disadvantages. ( c ) PVC, melamine, Polythene, natural ru bber 2 or soft solid as well made. A grater strength that the cotton fibres the air are highly cross-linked or. The polymer is a strong, lightweight and hard, thermosetting plastic is a thermoset plastic resin made melamine... To be non-recyclables a chemical interaction between specialized materials are synthetic substances Terylene is! As for as possible ru bber 2 does not rust like a bucket made thermosetting! Properties and appearance has made it a popular material for manufacturing hard wearing products across a number of smaller.. Despite being very useful, it is, therefore, known as thermoset! 12 a synthetic fibre out of the tensile strength of the thread Puzzle complete the security check access... Item, water and air well as made up of iron ID: •... Cotton thread a nylon thread showing that nylon thread has a grater strength that the cotton fibres Select the from.

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