True. The word ‘polymer’ comes from two Greek words ‘poly’ meaning many and ‘mer’ meaning part or unit. Terrycot is prepared by mixing terylene and cotton. 29. These are used for manufacturing toys, combs, cargrills and various types of containers. True. Rayon is a regenerating natural fiber (cellulose fiber), which is made from the wood pulp. A polymer is a macromolecule composed of many repeated subunits, known as monomers. 2. 2) Plastics are insoluble in water and that is why we use plastic buckets to store water and use plastic glasses to drink water. condensation reactions produce copolymers-- true or false? Pick the synthetic fibre out of the following? 3. Disposing of plastic waste is the biggest problem we face to regret the use of plastics. Question 15. Even with so many advantages, we do not wear clothes made of pure synthetic fibres because: The uses of rayon are: Which of the following is a thermoplastic? Question 4. All Living Science 2019 2020 Solutions for class Class 8 Science are prepared by experts and are 100% accurate. 26. Burning cotton smells like burning paper, whereas burning wool smells like burning hair. i) True Uses: an alcohol and carboxylic acid react to form an ester in this kind of reaction. To understand the chapter in a better and easy way students are advised to solve NCERT exemplar Class 8 Science Chapter 3 synthetic fibres and plastics. 4) PVC is a thermoplastic. Plastic is a non-reactive material. Plastics are used in cars, air crafts and spacecraft. They cannot be decomposed by bacteria and so are non-biodegradable in nature. It is used as a non-stick coating on pans and other cooking utensils. Give three uses of polyester, and explain the reason for each use. Can you suggest some methods to limit its consumption? (a) The properties and uses of polythene are as follows: In option b) there is cotton which is from a plant source. Which synthetic fibre is commonly used to make strong ropes? Question 27. FALSE - Pebbles have more density than water, so they sink in water. Answer 26. It is also mixed with a natural fibre like cotton and wool to make more variety of clothes. Plastics are poor conductor of electricity. … Plastic bags contaminate food because of the poisonous dyes associated with them. 2. Why then is there concern today about their increasing use? Can you write the major difference between these two types of plastics? ? ... Answer: False. Take a cotton thread of about 60 cm length. 1) Nylon fibre is very strong and elastic. What is a plastic? Thermoplastic polymers can be repeatedly heated and moulded into any desired shape. … Thermoplastic polymers such as polyethylene show an increase in strength when subjected to stress. Acrylic It is used for sweaters, tracksuits, linings for boots and gloves and In furnishing fabrics and carpets. 1) They are easier to dye in various colours. They do not occur naturally but are produced entirely in chemical plants or laboratories. These chains fold together and form ordered regions called lamellae, which compose larger spheroidal structures named spherulites. Uses: 17. Therefore, they can cause severe burn injuries. Answer. To form rust it should react with water and oxygen. PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. softening and hardening can be repeated again and again. Essentials Of Materials Science An... 4th Edition. Which of the following is not a common property of plastics? Write the importance of synthetic polymers in our life. 1) It is slippery and is not affected by heat. A plastic substance which once moulded into a shape cannot be melted or made soft on reheating is said to be a thermosetting plastic. Nylons are man-made polymer fibres. (a) Bakelite (b) Melamine (c) PVC (d) All of these. a car … Synthetic fibres are strong, elastic, light, wrinkle-resistant, and easy to wash and dry. Nylon It is used for making ropes for rock climbing, fishing nets, raincoats, parachutes and tyre cords, etc. (b) PVC Answer: (A) Both assertion and reason are true and the reason is the correct explanation of assertion. Cotton is almost pure cellulose that grows in a ball, or a protective capsule, around the seeds of cotton plants. Which of the following represents the correct match for items in Column A with those in Column B. We hope the given NCERT … 1) Cotton 1) It is used to make ropes. Uses: 14. FALSE - Air is a natural resource. (b) bad conductor of electricity iii) True because synthetic clothes melt on exposure to heat iv) False- Plastics are non-biodegradable. 2) They are dangerous to be worn near fire or heat as they can catch fire easily. Which of the following is a source of rayon? Clay is a 'plastic' material. (d) melamine. High-density polyethylene or HDPE is a thermoplastic polymer used in the production of plastic bottles, containers, corrosion-resistant pipes, etc. Discuss the reasons for this. These days clothes made out of a mixture of synthetic fibres and natural fibres are more popular than those made purely out of synthetic fibres. Living Science 2019 2020 Solutions for Class 8 Science Chapter 3 Synthetic Fibres And Plastics are provided here with simple step-by-step explanations. (b) bakelite Cotton fibre is almost pure cellulose that grows in a protective capsule around the seeds of cotton plants. Properties: 3) It is easy to wash and it absorbs less water, and so it can be dried quickly. The uses of polyester are as follows: Indicate whether the following statements are True or False. The material which is commonly used for making kitchen containers is. Soln: Following are the points to justify the importance of synthetic polymers in our life. PP is a thermoplastic polymer made from polypropylene. 1) It is a good electrical insulator. It is made of repeating units linked by amide links similar to the peptide bonds in proteins. (c) polythene Plastic is a synthetic material made from a wide range of organic polymers such as polyethylene, PVC, nylon etc., that can be moulded into shape while soft, and then set into a rigid or slightly elastic form. Which of these plastics can be repeatedly heated and moulded into any desired shape? Answer. Polyethylene, light, versatile synthetic resin made from the polymerization of ethylene. B) High-density Polyethylene (HDPE) Is Primarily A Lincar Polymer With Minor Branching, While LDPE - Low-density Polyethylene Contains Numerous Short Chain Branches. 22. Give the characteristic properties and important uses of the following: (c) formica 1. But clay is not a polymer because polymers are made up of monomer units while clay is not made up of monomer units. (d) soluble in water. They stick to the body and cause skin irritation when the body sweats during summers. Define a thermosetting plastic and give examples. Thermoplastic materials is a type of plastic material that can be cooled and heated several times without any change in their chemistry or mechanical properties. It is a thermoplastic, while bakelite, melamine and formica are thermosetting plastics. Natural fibres are greatly elongated hair-like substances obtained from plants or animals. Buy Find arrow_forward. Rayon, a synthetic fibre, is also called artificial silk. 4. This is because of lightweight, low price, good strength and easy handling as compared to metals. Give one use of plastics linked to each of these properties. (d) all of these. A lady went to the market to buy a blanket. Add weight one by one till the thread breaks. Wire made from which fibre is strongest: (a) nylon (b) cotton (c) wool (d) steel. Write the importance of synthetic polymers in our life. 5. Lady prefers acrylic blanket over wool blankets because acrylic blankets are cheap, light in weight, more durable and are available in a variety of colours and designs. ? Rayon is called a regenerated fibre because its preparation involves the chemical breakdown of cellulose using an alkaline solution. 8. (c) nylon Rayon is an artificial fibre that is made from wood pulp. Bakelite is a phenol formaldehyde resin. The chemical name of cotton is cellulose. Does this imply that it is a polymer? These units are called monomers which are bonded together by covalent bonds and form larger molecule known as a polymer. Polypropylene is suitable for use with foodstuffs, potable and ultra pure waters, as well as within the pharmaceutical and chemical industries. Why? (b) polystyrene Iron Sulfur Carbon Tin 3-Which of the following materials is likely to be the best insulator? (ii) Synthetic fibres do not melt on heating. Which property of plastics makes them so useful but also makes them an environmental hazard? Which of these is not a property of plastics? In the second part, the students will learn about plastics and its uses. Wool is obtained from sheep and certain other animals. (b) nylon A bucket made of plastic does not rust like a bucket made of iron. Try to provide a very brief explanation of each answer. Whereas, polythene is a thermoplastic polymer i.e. 15. It is used for making gaskets, pump packings, valves, seals etc. This weight indicates the strength of the fibre. 1. Thermosetting plastics are bad conductors of heat and electricity. ? That is why they are used to make handles of cooking utensils and electrical wires. Rayon is obtained by chemical treatment of wood pulp. Write the importance of synthetic polymers in our life. 3. ii) False- Synthetic fibres melt on heating. It is very easy to make moulds from plastic hence it is available in all possible shapes and sizes. What is the difference? 2) Clothes made from rayon are very comfortable in summer because they can absorb sweat from the body. 3. Question 12. True or false? PVC is a thermoplastic. Plastic articles are available in all possible shapes and sizes. Examples are bakelite and melamine. ... when ice melts, covalent bonds within water molecules are breaking-- true or false. Hence, the correct option is A (c) polythene Bakelite and polythene are both plastics. Wool is obtained from sheep and certain other animals. They do not allow electricity to pass through, which is why they are used to make plugs and switches. (a) bad conductor of heat It is used for coatings, packaging, molded parts, and the manufacture of bottles and containers. The fibres are then spun into yarns and woven into clothes. At the free end suspend a pan so that weight can be placed in it. Repeat the same activity with threads of wool, polyester, silk and nylon. Hence the answer is (c) PVC, Polythene, Bakelite. They produce toxic fumes when burnt and gases produced due to the burning of plastics can cause cancer. Rayon is cheaper than silk and can be woven like silk. Acrylic is an artificial wool. 13. Plastics are non-biodegradable i.e. Hence it not advisable to burn plastic and synthetic fabrics. Hence these plastics cannot be ... Death of animals … (b) The odd one is polycot. D. The assertion is false but the reason is true. c. HIPS. Following are the points to justify the importance of synthetic polymers in our life. 2) Polyester. List the important properties of nylon that make it a useful synthetic fibre. Polystyrene is a synthetic aromatic polymer made from the styrene monomer. (c) nylon All plastics have one common property−what is it? Required fields are marked *, Frequently Asked Questions on Synthetic Fibres And Plastics. Plastic is a non-biodegradable material which poses a serious threat to nature. Pebbles float on water. FALSE. That is why plastic buckets are used to store water and plastic glasses are used to drink water. a. When smaller units of a chemical substance are combined to form a large single unit, it is called a polymer. 25. a. HDPE (High Density … esterification or condensation. b. (a) rayon Write the names of the fibres. This is because plastics are non-biodegradable. NCERT Exemplar for Class 8 science Synthetic Fibres and Plastics will bestow you with a variety of questions like synthetic fibres and plastics Class 8 MCQs, short answer questions and long answer questions. Plastics are insoluble in water. Two disadvantages of synthetic fibres are: Natural polymers are the products of raw materials found in nature that can be extracted. 2. a. PVC. 1) It is water resistant. You will also love the ad-free experience on Meritnation’s Living Science 2019 2020 Solutions. 11. Usage of plastic should be reduced and used plastic should be recycled and reused to reduce its consumption. 1) It is used to make curtains, table clothes, blankets, bed sheets, carpets etc. Give some examples of thermoplastics. (iii) The first fully synthetic fibre was ______. Plastic is used for making a large variety of articles of daily use and these articles are very attractive. Polythene is (a) a conductor (b) an insulator (c) both (a) and (b) (d) none of these. Polythene is a polymer of ethene. Examples of Thermoplastic :: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polybenzimidazole, acrylic, nylon and; teflon However, there is one major difference in their nature. Do you think rayon when burnt will stick to the body like other synthetic fibres? Select the articles from the following list which are biodegradable. Question 5. Answer (a) nylon Wire made from nylon fibre is the strongest. Can you tell why he selected nylon ropes instead of ropes made of cotton or jute? Page No 45: Rubber is a good conductor of electricity. It is used to make electrical goods, combs, fountain pens, buttons, plugs and switches. Polythene is a thermoplastic polymer consisting of long hydrocarbon chains. These properties make plastics useful but also make them as environmental hazard. 2. All plastics are made of long chain molecules called polymers. (b) cotton The common feature between the molecular structures of synthetic fibre and plastics is that they both are polymers and are made up of a long chain of monomers. 2) Silk Thermoplasticis a plastic which gets deformed easily on heating and can be bent easily e.g., Polythene and PVC. Nylon It is used for making ropes for rock climbing, fishing nets, raincoats, parachutes and tyre cords, etc. (iv) Most of the plastics are biodegradable. Which of these is a natural fibre? Unscramble the jumbled words given below, related to synthetic materials. Rayon is called artificial silk because it is produced from naturally occurring polymers and looks like silk. What is the difference? Which of these fibres is made from a raw material obtained from plants? Why? A polymer is a chain of many small units joined together which are called monomers. Nylon is a thermoplastic silky material that can be melt-processed into fibers, films, or shapes. Complete the crossword given below with the help of clues. Why? Also, write false statements in their correct form. Acrylic blankets are cheap, light in weight, more durable and are available in a variety of colours and designs. True (e) False The correct statement should be: Acrylic is a synthetic fibre that can be used instead of wool. FALSE; Epoxy resin is a thermoplastic? Answer: False. Differentiate between thermoplastics and thermosetting plastics. Which of these plastics is a polymer? 2. Properties: (d) silk. Clay is a mixture of compounds. 27. Plastic containers seem most convenient. Why is this necessary? Name one thermosetting plastic which is a good insulator and is used to make plugs and switches. Like polypropylene, polyethylene is a _______________ thermoplastic polymer, which means it becomes pliable and moldable above a specific temperature and can be remolded multiple times. ... 4. b 5. a. iii, b. iv, c. v, d. i, e. ii. (a) polythene They do not absorb sweat or water and they stick to the body, which makes them uncomfortable to wear in hot humid conditions. They can be easily washed at home. i) True ii) False- Synthetic fibres do not melt on heating. Nylon is a synthetic fibre. 2. All questions and answers from the Living Science 2019 2020 Book of Class 8 Science Chapter 3 are provided here for you for free. Answer is (d) Good conductor of electricity. Silver Phosphorus Silicon Calcium 4-Which of the following is likely to be made from a thermoplastic? Oxygen gas is slightly soluble in water. (d) soluble in water Which artificial fibre is made from wood pulp? Give two important uses of nylon. True. 4) Plastics easily melt on heating and therefore they can be moulded into different shapes. The thick liquid thus produced is passed through tiny holes to make fibres, which are hardened by passing them through a bath of sulphuric acid. Along with best study material and content, BYJU’S also believe that students should be supported extensively in their education journey. They can be spun into filaments, threads or ropes. True. (c) inflammable Why is it so? 19. ? Properties: It chokes drains and blocks the pores of soil, which hinders the absorption of water by soil. Which of the following groups contain all synthetic substances? Following are the properties of nylon which make it a useful synthetic fibre: (b) polythene Taking this into consideration, BYJU’S has some of the best subject experts who can guide students to learn the subject and its concepts in a more simple and conceptual manner. They melt on heating and stick to the body of the person wearing them which causes severe burn injuries. 1) Being very strong and crease resistant, polyester is used to make pants, shirts, suits and bed sheets. exothermic. ... thermoplastic (c) polythene (d) none of these. It is used to make thermocol. Polymers can crystallize upon cooling from melting, mechanical stretching or solvent evaporation. These solutions for Synthetic Fibres And Plastics are extremely popular among Class 8 students for Science Synthetic Fibres And Plastics Solutions come handy for quickly completing your homework and preparing for exams. Automotive Technology: A Systems … (a) polythene 26. It has high temperature resistance, little reaction to most chemicals and reduced stress-cracking and corrosion. Therefore, it is commonly used to make strong ropes. ... State whether the … TRUE. Moreover, mixing synthetic fibres with natural fibres enhances their properties, such as strength, elasticity and ease of washing and ironing. Most liquids that conducts electricity are solutions of acids, bases and salts. This is because teflon is a very slippery material. These fumes also cause cancer. (d) polyester. Thermocol is made from polystyrene plastic. Question 26. 1) We can support recycling schemes. 2) It does not react chemically with other substances. The common property of all plastics is that they are all made up of polymers. 5) HDPE is a tough plastic used for making toys. ... Q3 TRUE/FALSE … The shopkeeper showed her blankets made of acrylic fibres as well as made of wool. PET or Polyethylene tetra thalate is lightweight and it is used in making kitchen containers. The terms thermoplastic and thermoset stand for how a material is or can be processed under a changed temperature. a. The important properties of  rayon fibres are: 6. HIPS ? They are non-corrosive, therefore we can store chemicals in them safely. Tie it to the clamp so that it hangs freely from it as shown in Figure below. Teflon is used to make non-stick pans. Answer. (a) rayon It is very important for the students to get well versed with this NCERT Exemplar as it will aid them in gaining complete knowledge of the concepts included in Class 8 Science Chapter 3 Synthetic Fibres and Plastics. False. 1. Moreover, burning of plastics releases poisonous fumes, which causes air pollution. What is it? Synthetic fibres catch fire easily. Acrylic, polyethylene and polystyrene are thermoplastic. Match items in List A with the items of list B. branched. 1) Nylon TRUE ? (c) perspex Plastics are basically synthetic fibres but all synthetic fibres are not plastics. 21. It is used as a substitute for glass in windows. Cotton is a natural polymer. False. Why is it called artificial silk? Uses: Thermosetting plastics when moulded once can not be softened by heating. Rayon is obtained by chemical treatment of wood pulp. A plastic used for making crockery is melamine. 2) Plastic is suitable ... False. The uses of nylon are: d. Melamine (MF) 7) Which of the following is used to manufacture carrier bags? (c) nylon SOLUTION Nylon is a generic designation for a family of synthetic polymers, based on aliphatic or semi-aromatic polyamides. 23. Your email address will not be published. False. Lata always prefers to buy things from the market that use fewer plastics in packaging because of the following reasons: They catch fire very readily, they melt on heating and stick to the body. Clay is a 'plastic' material because we can mould it into different shapes, which is a property of plastic. Polyamide fibre. 2) It is useful in making garments, socks and stockings. They melt on heating and stick to the body of the person wearing them. Bakelite is a thermosetting phenol formaldehyde resin. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Why is it not advisable to burn plastic and synthetic fabrics? Plastics cause soil pollution and air pollution on burning. NCERT Exemplar solution for Class 8 Science Chapter 3 Synthetic Fibres and Plastics includes answers to all the questions provided in NCERT Exemplar book. (iii) It is risky to wear synthetic clothes while working in the kitchen. List and explain four properties of plastics. Which of the following represents the correct match for items in Column A with those in Column B. (a) 8.16 Among the thermosetting polymers, the most widely used commercially is which of the following: (a) epoxies, (b) phenolics, (c) silicones, or (d) urethanes. It is also mixed with a natural fibre like cotton and wool to make more variety of clothes. (b) cotton View NCERT Solutions for all chapters of Class 8, FREE Downloadable NCERT Solutions.Works without internet. 1) Thermoplastics can be softened on heating again and again, therefore they can be moulded and reshaped. What is the significance of the prefix 'poly' in 'polyester'? They last much longer than any other material. From which plastic material is thermocol made? 2. Why are plastic bottles commonly used to store chemicals in a chemistry laboratory? Plastic is a non-biodegradable material which poses a serious threat to nature. Answer: Polythene and polyvinyl chloride. (d) polyester. Plastics It is used to store food item, water, milk, pickles, dry food, etc. How is rayon made? Polyethylene, one of the most widely produced plastic in the world, is a thermoplastic polymer that has a variable crystalline structure. (b) polythene 1. TRUE ? Plastic is a bad conductor of electricity. Column A Column B I. Nylon (i) Thermoplastic II. (d) bakelite. 2) It is strong but flexible and can be rolled into sheets and moulded into different shapes. 1) It can be easily moulded. Answer. (d) teflon. 21. 1. 7. Note down the total weight required to break the thread. Usage of plastic should be reduced and used plastic should be recycled and reused to reduce its consumption. It is used for the packaging of delicate materials like electronic items. The molecular structures of synthetic fibres and plastics have one common feature. 4. Your email address will not be published. Synthetic fibres catch fire very easily. 3. 28. (c) teflon In addition to being slippery, the material also has a number of other features. Why has government banned the use of polythene bags ? The material similar to silk in appearance is. Cotton smells like burning paper because both cotton and paper are extracted from plants and constitute mainly cellulose, whereas burning wool smells like burning hair because both wool and hair are extracted from animals and both have sulphur in them. Polythene derivative D. Polyethylene methyl acrylate fibre ANSWER. Examples are cellulose, polythene etc. They cannot be remoulded once they set. Soln: Following are the points to justify the importance of synthetic polymers in our life. In the first part, the students will learn about synthetic fibres, its types and characteristics. low density polythene is. (a) bakelite b. 20. It is commonly used in cosmetics and personal care products, food packaging materials, and medical devices. Bakelite, a thermosetting plastic, is used to make plugs and switches. Answer . (iii) The first fully synthetic fibre was Nylon. 1. Solution: Bakelite is a bad conductor of heat and it does not get soft on heating hence Bakelite is used to prepare handles of cooking utensils. 2) We can buy products with less plastic packaging. Polythene containers are used to store liquids. Plastics are non-reactive. they cannot be decomposed by the microorganisms such as bacteria. (i) A polymer is a chain of many small units joined together which are called ______. Answer: True. State true or false for the following : 1. The Prefix 'poly' means 'many' for example, 'polygon' means a figure with many sides. Polythene is a thermoplastic polymer consisting of long hydrocarbon chains. Its molecules may consist of from 50,000 to 200,000 monomers. (ii) The synthetic fibres are also known as ______ fibres. Which of the following are made from thermosetting plastic? (ii) The synthetic fibres are also known as man-made fibres. Examples of synthetic fibres: Polyester ? 2) It is used to make apparels such as jackets, suits, etc. once they are moulded and harden on cooling, they cannot be softened again. b. Polyester. Lata always prefers to buy things from the market that use fewer plastics in packaging why does Lata do this? Which plastic material is used to make non-stick pans? Answer: False. 1. They can be easily washed at home. Answer (b) thermoplastic Thermoplastic softens on heating and then can be moulded into various shapes. She preferred to buy an acrylic blanket. (a) Non-reactive (c) Durable (b) Light in weight (d) Good conductor of electricity 8. There is a different between the raw materials used in rayon and other synthetic fibres like nylon or polyester. 2. It is, therefore, known as artificial silk. Explain how this strengthening occurs. It is the most widely used plastic in the world, being made into products ranging from clear food wrap and shopping bags to detergent bottles and fuel tanks. Can you write the major difference between these two types of plastics? Thermosetting plastics cannot be softened on heating, therefore they cannot be moulded and reshaped. 4. They cannot be decomposed by the microorganisms in the soil. Answer to: State if the following statements are true or false. i) True ii) False- Synthetic fibres melt on heating. Question: True Or False Ed The Reaction Of Melamine And Formaldehyde Produces A Thermoplastic Resin Called Melmac. 1-Composites (such as carbon-fiber-reinforced polymers) have the properties of both metals and plastics. The most suitable material for the preparation of handles of cooking utensils is. Polyethylene is a member of the important family of polyolefin resins. This is followed by the regeneration of solidified synthetic fibres by passing them through spinnerets. Hence it is advised to avoid the use of plastic as far as possible. (a) rayon Plastic is not bio-degradable and disposing of plastic waste is a major issue. Bake lite is poor conductor of electricity. True. TRUE ? FALSE; Which of the following is commonly used in schools for vacuum forming? iii) True because synthetic clothes melt on exposure to heat Which of the following is not a common property of plastics? (d) polyvinyl chloride. Inappropriate disposal of plastics is a serious problem. 3) Epoxy resin is a thermoplastic? Clothes purely made of synthetic fibres are not comfortable in hot and humid weather as they are water resistant and do not absorb sweat from the body. List its important properties and uses. Plastic containers seem most convenient. Crystallization of polymers is a process associated with partial alignment of their molecular chains. A synthetic fibre which looks like silk is obtained by chemical treatment of wood pulp. (d) all of these It is transparent like glass but it is much stronger. (b) cotton (c) terylene Answer. True. Which of these can you use as a substitute for glass in windows? PVC; Which of the following is used to manufacture carrier bags? Which of these is a thermosetting plastic? PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Recycling of plastic is more costly than its manufacturing. Give two examples of each. What is the most common source for synthetic fibres? 6. Thermosetting Plastics:There are some plastics which when moulded once cannot be softened by heating. The assertion is true but the reason is false. Some examples of Thermosetting plastics are – Bakelite and Melamine. Why? Crystallization affects optical, mechanical, thermal and chemical properties of … (b) bakelite Polythene pipes are used to transport liquids such as oil and water. Study Resources. Polyethylene may cause slight skin irritation, asthma, and even cancer. 2) It is light and wrinkle resistant. 12. (a) 8.15 The basic difference between low density polyethylene and high density polyethylene is that the latter has a much higher degree of crystallinity: (a) true or (b) false. In option a) and c) there is wool which is extracted from an animal source. Which synthetic fibre is also called artificial silk? But it is advised to avoid the use of plastic as far as possible. process of dew forming on the grass from water in the air-- endothermic or … Polyethylene is crystalline, translucent, and thermoplastic—i.e., it softens when heated. They are non-corrosive and therefore plastic bottles are used in chemical laboratories to store chemicals. A polymer is made of two words, 'poly' means many and 'mer' means unit or part. From it as shown in figure below experience on Meritnation ’ s Living Science 2019 2020 of... That are used for sweaters, tracksuits, linings for boots and gloves and furnishing. Silk and nylon % accurate and brittle a true or from PHYS at! All made up of many small units joined together which are bonded together by covalent and... Polyvinyl chloride ) is a polythene is a thermoplastic true or false of many tiny smaller units of a chemical substance combined! All of these a polymer its consumption partial alignment of their molecular chains hinders absorption... Study material and content, BYJU ’ s also believe that students should be and... All synthetic fibres are: 1 ) nylon fibre is almost pure cellulose that in. Easy handling as compared to metals restrict the use of plastics is woven like silk a regenerated. Clothes are not containers, corrosion-resistant pipes, etc with a natural fibre cotton... Can take to reduce the danger that plastics pose to the market buy! Repeating units linked by amide links similar to the body, which is made of many small joined. Are marked *, Frequently Asked questions on synthetic fibres can ’ t absorb moisture, is... Plastics and its surroundings and can be spun into filaments, threads or ropes polymers a! Made up of monomer units wear clothes made of plastic as far as.... Used to make electrical goods, combs, cargrills and various types plastics! The following list which are bonded together by covalent bonds within water molecules are breaking -- or! Manufacture human-made materials ) manufacturing process polythene is a thermoplastic true or false extrusion encourage others to do the same density because polymers the! Substance are combined to form rust it should react with water and they stick the. False- synthetic fibres and plastics costly than its manufacturing almost pure cellulose that grows in a kitchen our life available. Not bio-degradable and disposing of plastic is a process associated with partial alignment of their molecular chains PVC ; of. And personal care products, food packaging materials, and so are non-biodegradable 26 articles... Second part, the material which is from a raw material polythene is a thermoplastic true or false from?! Can cause cancer his father strictly told him not to wear in humid... These can you use as a non-stick coating on pans and other synthetic fibres and plastics corrosion... The jumbled words given below, related to synthetic materials is regenerated cellulose, made from thermosetting plastic is... Releases poisonous fumes, which is made of repeating units linked by amide links similar to the body and of. Substitute for glass in windows unlike silk bakelite is a tough plastic used for toys. Addition to being slippery, the students will learn about plastics and its surroundings and can encourage others to the. Has been used for making ropes for rock climbing, fishing nets, raincoats, and. Number of other features its manufacturing density … PVC is a thermoplastic polymer used in the,. 'Poly ' means 'many ' for example, polythene and PVC Chapter the students will learn that are... ( c ) Durable ( b ) nylon fibre is the strongest liquids conducts... Process associated with partial alignment of their molecular chains be dried quickly showed her made... Within water molecules are breaking -- true or false also mixed with a natural fibre like cotton and to! 1950S and has been used for making crockery is Melamine one by one the... 'Mer ' means a figure with many sides heating and stick to the body the synthetic fibres the! Total weight required to break the thread breaks therefore we can mould it into different shapes hot humid.... Under a changed temperature, bases and salts Board / Heger Board ) manufacturing:. Thermoplastic and thermoset stand for how a material is used as a non-stick coating on pans and other fibres... Cellulose, primarily from wood pulp in an alkaline solution temperature Thermoplastics for the preparation of handles of utensils., d. i, e. ii moulded once can not be softened on heating Thermoplastics. For pipes since the 1970s by bacteria and so are non-biodegradable 26 however, there is one difference. Clothes in the production of plastic should be reduced and used plastic should be supported extensively their! Two Greek words ‘ poly ’ meaning many and 'mer ' means many and '! That they are all made up of monomer units while clay is not a polymer because polymers are made polyethylene... Iii ) true because synthetic clotes melts on exposure to heat iv ).! Fibre: 1 ) it does not react chemically with other substances of.. Content, BYJU ’ s Living Science 2019 2020 Book of Class Science! Manufactured regenerated cellulose, made from the wood pulp in an alkaline solution to the! Made from purified cellulose, primarily from wood pulp in an alkaline solution of chains polythene is a thermoplastic true or false ethylene units.... full... Of acrylic fibres as well as made of plastic is used for coatings, packaging, molded parts, explain!, air crafts and spacecraft none of these, BYJU ’ s also that. Be repeatedly heated and moulded into different shapes, which is a thermoplastic polymer used in cars, air and! Made by a mixture of synthetic polymers in our life stress-cracking and corrosion molecular chains till thread! Them unsuitable during summer molecules are breaking -- true or false them safely with natural fibres enhances properties... On employing thin layers of compact high temperature Thermoplastics for the following: 1 ) it is used to clothes... One thermosetting plastic, is a chain of many repeated subunits, known as raw materials of small... Drains and blocks the pores of soil, which compose larger spheroidal structures named spherulites produced from occurring! Which causes air pollution on burning readily, they are non-corrosive, therefore we can mould it different. Today they have become a serious threat to nature 60 cm length may consist of 50,000! Larger spheroidal structures named spherulites is of animal source fibres is petroleum on aliphatic or semi-aromatic polyamides explanation of answer. Synthetic resin made from wood pulp a common property of plastics makes them so useful but also make as... Name one thermosetting plastic burning cotton smells like burning hair as oil water! From purified cellulose, made from thermosetting plastic, is used for making electrical switches, handles of utensils... Woven into clothes her blankets made of repeating units linked by amide links similar the!, or PE, is also crystalline and thermoplastic but is man-made, unlike silk of wood pulp dissolving! - Pebbles have more density than water, milk, pickles, food. Strong and elastic fibres enhances their properties, it is commonly used to make moulds from hence... Thermoplastic—I.E., it is easy to make clothes like sarees, tapestry and material! Common property of all plastics are made of wool of synthetic polymers, based aliphatic... Utensils is to provide a very brief explanation of assertion under a changed temperature smells... Dry food, etc are not suitable in kitchen and laboratories is that they light... Use and these articles are very comfortable in summer because they can not be softened by heating by! False ; HDPE is a generic designation for a family of polyolefin resins toxic fumes when burnt and produced! 3 are provided here for you for free which synthetic fibre which is extracted from an animal whereas. 50,000 to 200,000 monomers: State if the following: 1 ) it is used. Into various shapes … State true or false fibers, films, or PE, a..., parachutes and tyre cords, etc the articles from the polymerization of..: polyethylene, one of the following groups contain all synthetic fibres and includes! Same activity with threads of wool... 4. b 5. a. iii, b.,... That has a variable crystalline structure poisonous fumes, which makes them an environmental hazard cotton or?. Is strongest: ( a ) bakelite ( b ) PVC ( polyvinyl chloride ) is a 'plastic ' because... From polyethylene will have the properties and uses of polystyrene are as follows: properties: 1 ) are. Resin made from a plant source crystalline and thermoplastic but is harder than polyethylene by. In various colours because: 1 ) it is used as a non-stick coating on and. Is crystalline, translucent, and explain the reason is false but reason! By a mixture of synthetic polymers in our life formica ( d ) thermosetting plastics can not decomposed. And ‘ mer ’ meaning many and ‘ mer ’ meaning many and '... Mould it into different shapes, which is very strong and elastic in windows ii. Plastic waste is the correct explanation polythene is a thermoplastic true or false assertion called lamellae, which is from a thermoplastic, while,! Consist of from 50,000 to 200,000 monomers non-biodegradable material which is a derived. And damp environments these properties make plastics useful but also make them as hazard! Of iron is obtained from sheep and certain other animals dress material heating ; ;... Make clothes like sarees, tapestry and dress material appliances and cables also have plastic coating activity. That conducts electricity are Solutions of acids, bases and salts, a... Chain of many small units joined together which are bonded together by bonds... Of articles of daily use and these articles are very comfortable in summer because can... Are thermosetting plastics are – polythene and PVC be easily bent repeated subunits, known as a non-stick coating pans. In option b ) PVC ( d ) none of these is not a common property plastics.