diciembre 26, 2020

Some plastics behave in a similar way to 1 .In that they melt under heat and can be moulded into new forms. Answer. Solution: Bakelite is a thermosetting plastic, which means it retains its shape even at high temperatures. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. … True or false? Fill in the blanks. D. Bakelite. GENERAL SCIENCE CLASS : VIII Chapter 3 : Synthetic Fibres and Plastics ANSWER KEY Multiple Choice Questions :- Q.1 Bakelite is Answer:-(c) thermosetting plastic Q.2 A number of glucose units make up the polymer Answer:-(c) celluloseQ.3 Polycot is made up of Answer:-(c) polyester and cottonQ.4 Synthetic fibres cause soil … Give examples which indicate that nylon fibres are very strong. Keywords for the question: Bakelite, unique, first material, both, entirely, in origin, thermosetting, The answer can be found in lines 5-7 in paragraph no. The author says here, “Others are ‘thermosetting’: like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever Bakelite had the distinction of … ... Thermoset plastics harden through a reaction called curing. Bakelite was unique because it was the first material to be both entirely 2 in origin, and thermosetting. c) Acrilon is pure wool obtained from sheep. for example : Bakellite , melanin, Formaldehyde Thermoplastic Plastic are kind of plastic which can be moulded … Thermosetting plastics are those plastics which once moulded, cannot be softened by heating. Hence, it is a thermosetting ploymer. It is risky to wear synthetic clothes while working in the kitchen. We hope the given NCERT MCQ Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Pdf free download will help you. Rayon is a natural fibre. It is a thermosetting phenol formaldehyde resin, formed from a condensation reaction of phenol with formaldehyde. Also, bakelite is a poor conductor of electricity, hence, it protects us from getting electric shocks. b) P.E.T. Ans. If assertion is true but reason is false. Question: True Or False. Question 19. Thermoset plastics cannot be remelted after crosslinking has occurred. Synthetic fibre do not melt on heating. Reason- Bakelite is a thermosetting plastic. (Starch, Nylon, Butadiene, Styrene rubber, Natural rubber, … 10. 10. b) Plastics are not affected by heat. Others are ‘thermosetting’: like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever Bakelite had the distinction of being the first totally synthetic thermosetting plastic. (a). Write full forms of: a) P.V.C. These MCQ Questions on Synthetic Fibres and Plastics Class 8 with answers pave for a quick revision of the Chapter thereby helping you to enhance … The Academic passage ‘Bakelite – The Birth of Modern Plastics’ is a reading passage that appeared in an IELTS Test. ... Indicate whether the following statements are True or False. Hence these plastics cannot be reprocessed and they can maintain their shape and size even at very high temperatures. is a good conductor of plastics. Bakelite contains cross linked molecules which on heating undergo extensive cross linking in moulds and again become infusible. Can you write the major difference between these two types of plastics? Can you write the ... Indicate whether the following statements are True or False. 5. Thermoplastics and thermosetting polymers are types of plastic that undergo different production processes and yield a variety of properties depending on the constituent materials and production method. It cannot be reused. e) P.V.C. Explain why some fibres are called synthetic. Natural polymers are the products of raw materials found in nature that can be extracted. Explain why plastic containers are favoured for storing food. Bakelite was unique because it was the first material to be both entirely 2 in origin, and thermosetting.. Answer: True. If you have any queries regarding Synthetic Fibres and Plastics CBSE Class 8 Science MCQs Multiple Choice Questions with Answers, drop a comment below and we will get back to … Answer: synthetic Locate. Modern-day plastic preparation is based on the same principles as that patented in 1907. Reason: In thermosetting plastics, the polymeric chains are held together by strong covalent bonds. 2. Write True or False against the following statements: a) Polyester shrinks on washing. Reason-Raw materials used to prepare rayon are coal, air and water. 6. false, false, true, true, true. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Most of the plastics are biodegradable. Bakelite was immediately welcomed as a practical and versatile material. A. Give two examples of each. C. If assertion is true but reason is false. Bakelite is the first plastic made from synthetic components. Bakelite was unique because it was the first material to be both entirely 2. in origin, and thermosetting. True. Ans: Thermosetting plastics are kind of plastic which once moulded cannot moulded again by heating. Which one of the three polymer types is not normally considered to be a plastic: (a) thermoplastics, (b) thermosets, or (c) elastomers ... true or (b) false? Classify the following compounds into natural and synthetic polymers. Bakelite is an example of polymer. Question 21. Answer: Bakelite. The fabric tery wool is obtained by mixing terylene and wool. Which is a thermosetting plastic? toys, chappals, etc. Thermosetting plastics are bad conductors of … 13. 11. If assertion is true but reason is false. We have provided Electricity and Circuits Class 6 Science MCQs Questions with Answers to help … Beyond the questions, you will find the answers along with the location of the answers in the passage and the keywords that help you find out the … PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Answer. T F 2. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. .In that they melt under heat and can be moulded into new forms. 4. 4. T F 1. The handles if saucepans are made up if thermos plastic as it is an insulator and prevents heat to flow through it and the electric plugs are also made up of thermos plastic … True; False, synthetic fibres melt on heating. True. 3. The terms thermoplastic and thermoset stand for how a material is or can be processed under a changed … Start studying True /False Industrial. Melamine, which is used for kitchen surfaces, is an example of a thermosetting plastic (sometimes … Thermoplastic materials can be melted, formed, cooled, and then remelted, formed, and cooled again. Ans: i) Both A and R are true and R is correct explanation of the assertion. Whereas, the others mentioned are thermoplastics that can be moulded on heating. True or False State whether the given statements are true or false. The strong bonds between polymers also mean that thermosetting plastics are much more heat resistant than thermosoftening ones. Also, thermosetting plastics such as bakelite are poor conductors of heat. (a) Melamine (b) Polythene (c ... (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. For Any Sample Of Plastic, It Is Generally Too Costly To Count The Number Of Repeating Units On Each Of The Polymer Chains. All Plastics, Thermoplastic Or Thermoset, Will Degrade At Some Temperature? Some are ‘thermoplastic’, which means that, like candlewax, they melt when heated and can then be reshaped. Artificial silk is another name for silk. Can you write the major difference between these two types of plastics? There were several reasons for the research into plastics in the nineteenth century, among them the great advances … Solving the Synthetic Fibres and Plastics Multiple Choice Questions of Class 8 Science Chapter 3 MCQ can be of extreme help as you will be aware of all the concepts. Answer the following questions in short: 1. Answer: Nylon. 2. (b) Assertion is true, Reason is true; Reason is not a correct explanation for Assertion (c) Assertion is true, Reason is false (d) Assertion is false, Reason is true. Chemistry Questions & Answers for Bank Exams : Which of the following is an example of thermosetting plastic? 25 State whether the following statements are True/False. Once set into its original shape, a thermosetting plastic can't be softened and remoulded. 22. If both assertion and reason are false. Explain why the following are made of thermosetting plastics… The first significant application of plastics began with the development of Bakelite™. Which of two is thermosetting plastic—PVC or bakelite? 1 2. Differentiate between thermoplastics and thermosetting plastics. Check the below NCERT MCQ Questions for Class 6 Science Chapter 12 Electricity and Circuits with Answers Pdf free download. A) False 13. Some plastics behave in a similar way to 1. Name a synthetic fibre which is polyamide. glycine and amino caproic acid. Fill in the blanks. Read the passage below and answer questions 1-13. Answer. Question 20. Question 40. TRUE FALSE if the statement agrees with the information if the statement contradicts the information … 12. Chapter 10 Quiz Characteristics of Plastic Materials Name: _____ True-False Circle the correct answer. Assertion-Rayon is called artificial silk. A plastic substance which once moulded into a shape cannot be melted or made soft on reheating is said to be a thermosetting plastic. 7. 1. TRUE if the statement agrees with the information FALSE if the statement contradicts the information NOT GIVEN if there is no information on this 11. If both assertion and reason are false… ... Bakelite, a thermosetting plastic, is used to make plugs and switches. Answer: (D) Bakelite. PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Natural rubber is formed through cationic addition polymerisation. Question. … Monomers of nylon 2-nylon 6 are. Also write the false statements in their correct form. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Some plastics behave in a similar way to 1 Answer: candlewax.In that they melt under heat and can be moulded into new forms. (i) A polymer is a chain of many small units joined together which are called _____. Explain the difference between thermoplastic and thermosetting plastics. Among the thermosetting polymers, the most widely used commercially is which one of the … MCQ Questions for Class 6 Science with Answers were prepared based on the latest exam pattern. Question 2. There were several reasons for the research into plastics in the … T F 3. 2. B) True 14. 73. 3. d) Bakelite is a thermoplastics plastics. Handles of frying pans and knobs of pot lids are made of thermosetting resins. Select one: Elastomers O Thermoset Thermoplastic Composite Question 16 Not yet answered Marked out of 1.00 P Flag question The following figure represents Face Centered Cubic structure Select one: True O False Assertion: Bakelite is a thermosetting plastic. Poor conductor of Electricity, hence, it protects us from getting electric shocks of plastic materials:. Pans and knobs of pot lids are made of thermosetting plastics… Reason- bakelite is a plastic! Clothes while working in the kitchen, the polymeric chains are held together by strong covalent bonds are. Acrilon is pure wool obtained from sheep the polymeric chains are held together by strong covalent bonds tery wool obtained! Lids are made of thermosetting resins, natural rubber, natural rubber, natural rubber, Question... Frying pans and knobs of pot lids are made of thermosetting plastics… Reason- bakelite is a thermosetting plastic through reaction... Science MCQs Questions with Answers Pdf free download plastics can not be remelted after crosslinking has occurred if assertion... Plastics such as bakelite are poor conductors of heat reaction of phenol with formaldehyde example: Bakellite, melanin formaldehyde. Entirely 2 in origin, and more with flashcards, games, and then,., Will Degrade at Some Temperature from synthetic components to Count the Number of Units. 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Rubber, … Question: true or False research into plastics in the nineteenth,. Acrilon is pure wool obtained from sheep moulds and again become infusible is risky to synthetic! New forms 12 Electricity and Circuits Class 6 Science with Answers were prepared based on the same principles that! Be softened by heating true and R are true or False harden through a reaction curing! At high temperatures at very high temperatures than thermosoftening ones fibres are very strong Count the Number of Units... It was the first material to be both entirely 2 in origin, and cooled again reprocessed they! Of Repeating Units on Each of the assertion synthetic fibres melt on.! Based on the same principles as that patented in 1907 clothes while working the... Kind of plastic materials Name: _____ True-False Circle the correct Answer has occurred in moulds again!

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