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9th Class Science Chapter 14 Substance in Common Use Exercise | Class 9 Lesson 14 Question Answer



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9th Class Science Chapter 14 Substance in Common Use Exercise | Class 9 Lesson 14 Question Answer

Exercise class 9 science chapter 14 substances in common use । Exercise substances in common use

Exercise class 9 science chapter 14 substances in common use, Exercise substances in common use , Question answer class 9 science, Std 9 science and technology, Class 9 science and technology, Fill in the blanks. a. The number of molecules of water of crystallization in washing soda is ….. b. The chemical name of baking soda is …. c. ….. is used in treatment of hyperthyroidism. d. The chemical name of Teflon is …. 2. Match the pairs Group A Group B 1. Saturated brine a. sodium metal freed 2. Fused salt b. basic salt 3. CaOCl2 c. crystallization of salt 4. NaHCO3 d. oxidation of colour 3. Write answers to the following a. What is meant by radioactivity? b. When is said to be the nucleus unstable? c. Which diseases are caused by artificial food colours ? d. Where in the industrial field is radioactivity used? e. Write down properties of teflon. f. What type of colours will you use to celebrate ecofriendly Rang Panchami? Why? g. Why has the use of methods like Teflon coating become more common? 4. Give scientific explanation a. Bleaching powder has the odour of chlorine. b. The hard water of a well becomes soft on adding washing soda to it. c. Soap forms a precipitate in hard water. d. The particles of powder are given an electric charge while spraying them to form the powder coating. e. The aluminium article is used as an anode in the anodising process. f. When the radiation coming out from certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path. g A certain type of ceramic tiles are fixed on the outer layer of a space shuttle. 5. Write answers to the following a. Write about artificial food colours, the substances used in them and their harmful effects. b. What is meant by water of crystallization? Give examples of salts with water of crystallization, and their uses. c. Write briefly about the three methods of electrolysis of sodium chloride. 6. Write the uses. a. Anodizing b. Powder coating c. Radioactive substances d. Ceramic 7. Write the harmful effects a. Artificial dye b. Artificial food colour c. Radioactive substances d. Deodorant 8. Write the chemical formula Bleaching powder, common salt, baking soda, washing soda 9. Explain what you see in the following picture Project : Visit the places where powder coating, Teflon coating is done. Get information about the process and present it in the class. Ceramics can withstand high temperatures without decomposing. Ceramic is brittle, water resistant and an electrical insulator. Therefore, it is used in electrical instruments, for coating the interior of a kiln, the outer surfaces of ships and blades of jet engines. A certain type of ceramic tiles are fixed on the outer layer of a space shuttle. Some types of ceramics are used as superconductors. Exercises ²
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