Example : Polyethene, Polyvinyl chloride (PVC) etc. i)Synthetic fibres are very strong and durable. v) Do not throw plastic waste in the street on the pavement or in drains. The term polymer means large molecules with higher molecular mass. Will you help her? These are used for manufacturing toys, combs and various types of containers. Which type of fibre is used in his sweater? Do Not Burn Plastic and Synthetic Fabrics. Nylon is another man-made fibre. Try to minimise the use of plastic materials. Most of the thermoplastics can be recycled. Towards the end of the nineteenth century, scientists were successful in obtaining a fibre having properties similar to that of silk. ii) Buy products without a little plastic packaging. Burning of plastics and synthetic fabrics produces lots of poisonous gases causing air pollution. Odd one out: choose the letter of the word that is not related from the other choices. A material which is not easily decomposed by natural processes is termed as non-biodegradable. Some examples are natural gas or even corn, wheat, or rice. We have provided Polymers Class 12 Chemistry MCQs Questions with Answers to help students understand the concept very well. Why do people choose this type of sweaters? Why? The word ‘polymer’ comes from two Greek words; “poly” meaning “many” and “mer” meaning “part/unit”. Explain. This fibre was called rayon or artificial silk. After studying the NCERT Books, important Questions provide a proper revision of the chapter for exams. So, a polymer is made of many repeating units. Acrylic blankets are cheap, light in weight, more durable and are available in variety of colours and designs. 2) The burning of plastic waste gives out harmful gases which pollute the air. Fire proof plastic uniform worn by fire fighters has a coating of _____ to make it fire resistant. Bakelite definition, a brand name for any of a series of thermosetting plastics prepared by heating phenol or cresol with formaldehyde and ammonia under pressure: used for radio cabinets, telephone receivers, electric insulators, and molded plastic ware. We should use of bags made of cotton or jute instead of plastic bags when we go for shopping. All organic compound comes to this category. Would you like to help him? “In every year, Boojho likes to wear a sweater which appear to resemble like wool”. Cellulose is made up of a large number of glucose units. For manufacturing synthetic fibres cutting of trees or killing of animals is not required and we can conserve our natural environment using synthetic fibres. (adsbygoogle = window.adsbygoogle || []).push({}); Copyright 2021 by Tiwari Academy – A step towards Free Education, NCERT Solutions for Class 8 Science Chapter 3, Class 8 Science Chapter 3 Important Questions. Examples – Bakelite, Melamine, Silicone, Epoxy. Such as animals, trees, cotton, jute. The coating on modern non- stick cookware and electric iron is of Today if we think of storing a food item, water, milk, pickles, dry food, etc., plastic containers seem most convenient. Synthetic fibres are more durable and affordable which makes them more popular than natural fibres. Discuss. Nylon is also used for making parachutes and ropes for rock climbing. Some examples of their use are the packaging of tablets, many bottles, threads used for stitching wounds, syringes, doctors’ gloves and a number of medical instruments and so on. Many such small units combine to form a large single unit called a polymer. i) Avoid the use of plastics as far as possible. We need not produce resources on large scale which may lead to exploitation of natural resources. Such as animals, trees, cotton, jute. Download NCERT Books 2020-21 based on new CBSE Syllabus for session 2020-2021. Bakelite is a thermosetting plastic, it cannot be molded again whereas Melamine, being a thermoplastic, can be molded any number of times adn reshaped. Justify the statement. A material which gets decomposed through natural processes, such as action by bacteria, is called biodegradable. These monomers add together to form a long chain to form a product with spe… The fabric melts and sticks to the body of the person wearing it. Orientation of monomer units in a polymer molecule A. Tacticity B. Graft C. Linear D. Monomer arrangement 11. 2) Reuse: Resources can be reused wherever possible. We can store various kinds of chemicals and other materials in plastic containers because they are non-reactive and does not react with water and air. These are called synthetic fibres. But plastics do not react with water and air. When we add hot water to a plastic bottle, it gets deformed. a) Terrycot. Such as plastic. Tutorial for Learning C Programming: Is It Possible to Learn the Programming Language Online. It contributes sturdy structure to the plants. Classify the following into thermosetting and thermoplastics-combs, bakelite, melamine, toys. Fabric made from this fibre does not get wrinkled easily. Plastic causes environmental pollution. These cannot be re-melted. 2) Bakelite is a poor conductor of heat and electricity so, it is used for making electric switches and handles of the utensils. Addition polymers: Polymers are formed by the repeated addition of monomers with double and triple bonds. Orientation of monomer units in a polymer molecule, A type of polymer wherein the side groups are arranged in an irregular or random, Monomers made of alkenes usually undergo addition polymerization due to their. 8 Bakelite and Melamine are examples of. “Despite being very useful, it is advised to restrict the use of plastic”. This is actually a disadvantage of synthetic fibres. There are some of the steps which contribute towards the reducing the use of plastic materials by us. All organic compound comes to this category. Polyester is another synthetic fibre. Although synthetic fibre catches fire easily, it is interesting to know that the uniforms of firemen have coating of “melamine plastic” to make them flame resistant. Course Hero is not sponsored or endorsed by any college or university. Melamine is a versatile material. It can be drawn into very fine fibres that can be woven like any other yarn. A synthetic fibre is also a chain of small units joined together. Give example to show that plastics are non-corrosive in nature. Answer: (c) 10. Class 8 Science Chapter 3 Important Questions of Synthetic Fibres and Fabric. Although rayon is obtained from a natural source, wood pulp, yet it is a man-made fibre. The polybags carelessly thrown here and there are responsible for clogging the drains, too. If the clothes catch fire, it can be disastrous. These are called thermosetting plastics. Therefore, people always prefer to choose plastic instead of using metals. Today, formica and medium density fiberboard (MDF) are still made by mixing bakelite with paper pulp or … The exemplar has been provided by the National Council of Educational Research & Training (NCERT) and the candidates can check it from below for free of cost. “As a responsible citizen remember the 4R principle”. iv) Synthetic fibres are extremely fine and shiny. Question 14. iii) Use bags made of cotton or jute or recycled paper, when you go for shopping. Synthetic fibres possess unique characteristics which make them popular dress materials. Answer: (a) 9. 4) Recover: We can recover or restore the resources into their original state, wherever possible. In 1927 the Bakelite patent expired. use a steel lunch box instead of a plastic one. Cotton is a natural polymer, called cellulose. Generally, people love to wearing polyester shirts and other dresses. Some important properties of bakelite are listed below. The plastic material chokes the respiratory system of these animals, or forms a lining in their stomachs and can be the cause of their death. Esters are the chemicals which give fruits their smell. Bataan Peninsula State University in Balanga, Bataan Peninsula State University in Balanga • BSME 101, Cracking the Sat Biology E_M Su - The Princeton Review.pdf, Bataan Peninsula State University in Balanga • CEA 0223, Bataan Peninsula State University in Balanga • BSAR 13-00215, Bataan Peninsula State University in Balanga • BSME 5C, Bataan Peninsula State University in Balanga • NURSING 103, Bataan Peninsula State University in Balanga • CHEM MISC. Polyvinyl chloride has heavy metals such as cadmium and lead which are toxic and harmful to our health. What Policies Can Help Students Affected by COVID-19? Class 8 Science Chapter 3 Important Questions are given below updated for new academic session 2020-21. The first human-made plastics were actually made using cellulose from plants. This is because of their light weight, lower price, good strength and easy handling. v) Synthetic fibres absorb very little water. It can be quickly molded. Ask your doubts related to NIOS or CBSE Board and share your knowledge with your friends and other users through Discussion Forum. Can you suggest some methods to limit its consumption? a) Nylon b) Rayon c) Melamine plastic d) Silk. Can you write a name of a “Natural polymer”? Define the term synthetic fibre. See more. For example, polyethene and polyvinyl chloride. Can you guess why? We should develop habits which are environment friendly. The chemical formula of bakelite can be written as (C 6 H 6 O-CH 2 OH) n. What are the Desirable Properties of Bakelite? Metals like iron get rusted when left exposed to moisture and air. A common example of linear polymer A Bakelite B Melamine C Branched D Poly. Plastics find extensive use in the health-care industry. The shopkeeper showed her blankets made up of acrylic fibres as well as made up of wool. Question 7. b) Silk. Plastics are often made from petrochemicals like crude oil but can also be made from other materials. How does plastic create problems for them? Such as plastic. Question 25. Synthetic fibres are man-made fibres. Bakelite items, particularly jewelry and radios, have become a popular collectible. In the process of eating the food waste from dump of garbage – “they swallow materials like polythene bags and wrappers of food”. Write down their some features. Each small unit is actually a chemical substance. It is advised to restrict the use of plastic because of the following reasons: 1) The articles made of plastics are non-biodegradable. Plastics are poor conductors of heat and electricity. Besides, the burning process in the synthetic material is quite slow and it does not get completely burnt easily. Terylene is a popular polyester. Important Questions and Extra questions are prepared to revise the chapter 3 of Class 8 Science. Based on the mode of polymerisation, it is classified into I. “A lady went to a market to buy a blanket. It resists fire and can tolerate heat better than other plastics. MCQ Questions for Class 12 Chemistry with Answers were prepared based on the latest exam pattern. Examples – Bakelite, melamine, etc. Polythene and PVC are some of the examples of thermoplastics. Question 12. Answer. Polymers are generally formed by the addition of a network of structural units or small molecules called monomers. It is used for non-stick coating on cook-wares. In the process it releases lots of poisonous fumes into the atmosphere causing air pollution. Programming Language Online users through Discussion Forum are reactive molecules and are usually linked to each other endorsed any. Of polymerisation, it is further classified into i Rayon 9 fire plastic. 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