Ask your interesting physics related questions for free. Polymer, any of a class of natural or synthetic substances composed of very large molecules that are multiples of simpler chemical units. 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. Bakelite is an example of thermoplastic. D. CH 3 COCH 3. State, whether the following statements are True or False. MCQ Questions for Class 8 Science with Answers were prepared based on the latest exam pattern. 5M 104. Start studying True /False Industrial. Explanation: It is a rigid type of plastic which is highly resistant to heat. Urea, Ammonia nitrate and ammonium sulphate are examples of: a) Nitrogenous Fertilizers b) Potassic Fertilizers c) Phosphatic Fertilizers d) None of these 3. Following are the two important polyester polymers:(i) Dacron or Terylene : When ethylene glycol (ethane–1, 2–diol) is condensed with terephthalic acid (benzene-1, 4-dicarboxylic acid) at 423–473 K, terylene is obtained. Play this game to review English. PVC – (ii) Thermosetting plastic . The reason why a plastic cup placed inadvertently near the fire becomes deformed is that it is made of a thermoplastic resin. Melting temperature increases with higher degree of crystallinity. It is different from thermoplastic resins which are known to be viscous liquids when heated to their melting points. 13. Bakelite – (iii) Fibre. Polymers make up many of the materials in living organisms, and they constitute the basis of certain minerals and human-made materials, such as paper and plastics. Artificial silk is another name for silk. (ii) All polymers are natural materials. Examples - Bakelite, Urea-formaldelyde resins • Addition Polymerisation or Chain Growth Polymerisation: Addition polymerisation is called chain growth polymerisation because it takes place through stages leading to increase in chain length and each stage produces reactive intermediates for use in next stage of the growth of chain. How states have been keeping small business afloat. Question 5. Examples – B akelite and melamine. Add your answer and earn points. State True or False (i) Nylon is a polymer. Statement: The articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled. 10) study guide by gadler95 includes 67 questions covering vocabulary, terms and more. 5. Say TRUE or FALSE : Chloroprene is an addition polymer of Neoprene. Bakelite is obtained from phenol by reacting with (a) Vinyl chloride (b) Ethylene glycol (c) Ethanal (d) Methanal Answer: (d) Methanal. Bakelite is obtained from phenol by reacting with [AIEEE 2008] A. HCHO. An important example of this class of substrates is the low cost epoxy-based FR4 laminate. Pressure cookers are quite heavy even without the metal handles. Active Science Solutions for Class 8 Science Chapter 3 Man Made Materials are provided here with simple step-by-step explanations. (a). Bakelite is a thermosetting polymer i.e. 4. MSE 2001 Exam 4 (Ch. 2. Quizlet flashcards, activities and games help you improve your grades. The material similar to silk in appearance is (a) Nylon (b) Rayon ... Thermoplastic . Nylon was made in 1931. (b). [TRUE/FALSE] Urea is an excellent nitrogenous direr which contains nitrogen about: a) 36% b) 47% c) 80 % d) 60% 4. A substance which has a molecular structure built completely from a large number of similar units bonded together known as polymers. Bakelite and melamine are thermoplastics( true or false) - 14613642 ... School +5 pts. once they are moulded and harden on cooling, they cannot be softened again. 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. 2. Question 5. Bakelite is an example of the thermosetting plastic. 3. Whereas, polythene is a thermoplastic polymer i.e. 3. 9 and Ch. We have provided Electricity and Circuits Class 6 Science MCQs Questions with Answers to help students understand the concept very well. Why are cells called structural and functional units of living organisms? These are the condensation polymers of diacids and diols. Deformed easily on heating and can bern easily is phenol by reacting with [ AIEEE 2008 ] HCHO! C ) melamine softened again for the polymerisation polymer, any of a thermoplastic resin polymers of and. Competitve exams and quiz only once i.e called structural and functional units of living?... 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