9th
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- Write the chemical formula Bleaching powder, common salt, baking soda, washing soda The chemical formula of bleaching Powder is CaOCl₂. The chemical formula of common salt is NaCl The chemical formula of baking soda is NaHCO... 1
- Explain what you see in the following picture This picture shows the process of powder coating. A polymer resin, a pigment and some more ingredients are melted, mixed, cooled and ground... 1
- write uses of Ceramic They are used in making roofing tiles, construction bricks, pottery, terracotta etc. Special type of ceramics are used in outer surfaces of... 1
- write uses of Radioactive substances It is used as a fuel in nuclear reactors to generate power. It is used in controlling the thickness of paper, plastic and metal sheets durin... 1
- Write uses of Powder coating It makes painted architectural steel parts resistant to heat damage, cold damage and even corrosion. Most of metal products designed to be u... 1
- Write the uses of Anodizing Anodizied cooking utensils like griddles cookers and pans are nonstick, scratch resistant and can be easily cleaned. Anodized utensils are h... 2
- Write briefly about the three methods of electrolysis of sodium chloride. When an electric current is passed through a saturated solution of sodium chloride (brine) it is electrolysed and hydrogen gas is released a... 1
- What is meant by water of crystallization? Give examples of salts with water of crystallization, and their uses. Water of crystallization is a fixed number of water molecules present in the crystal structure. Substances in our daily use which contain sa... 1
- Write about artificial food colours, the substances used in them and their harmful effects. Artificial food colours used for : For Red colour : Ponceau 4 R, carmoisine and erythrosine. For yellow colour : tetrazene and sunset yellow... 1
- A certain type of ceramic tiles are fixed on the outer layer of a space shuttle. A certain type of ceramic tiles are fixed on the outer layer of a space shuttle. They are made from alumina (Al₂O₃), zirconia (ZrO₂), silica... 2
- When the radiation coming out from certain radioactive substance is passed through an electric field, When the radiation coming out from certain radioactive substance is passed through an electric field, marks of three distinct spot are found... 1
- The aluminium article is used as an anode in the anodising process. A protective layer is formed naturally on the surface of aluminium metal by reaction with oxygen in air. In the anodizing process, this laye... 1
- The particles of powder are given an electric charge while spraying them to form the powder coating. Powder coating is a method of applying a layer harder than paint on the surface of an iron object to prevent rusting. In this method, a poly... 1
- Soap forms a precipitate in hard water. When soap is added to hard water, the displacement of sodium takes place and calcium, magnesium salts of fatty acid are formed. Since these... 1
- The hard water of a well becomes soft on adding washing soda to it. The hardness of hard water is due to the presence of chlorides and sulphates of calcium and magnesium. When washing soda (Na₂CO₃. 10H₂O) is... 1
- Bleaching powder has the odour of chlorine. Chlorine is the main constituent of bleaching powder. When exposed to air, bleaching powder reacts with carbon dioxide in air to produce cal... 1
- Why has the use of methods like Teflon coating become more common? Teflon is a substance which is inert to chemicals, stable at higher temperatures, easy to clean and nonstick. All these properties make it a... 1
- What type of colours will you use to celebrate ecofriendly Rang Panchami? Why? We should use natural colours made from plants for celebrating an echo friendly Rang Panchami. These natural colours can be made from natura... 1
- Write down properties of teflon. Teflon has the following properties: It is not influenced by the atmosphere and chemical substances both water and oil do not stick to the T... 1
- Where in the industrial field is radioactivity used? Radioactivity has various industrial application: It is used as a fuel in nuclear reactors to generate power. Internal cracks and voids in c... 1
- Which diseases are caused by artificial food colours ? Colours used in pickles, jam and sauces contain lead and mercury in small quantities. Regular consumption of these products can be dangerous... 1
- When is said to be the nucleus unstable? Nucleus of certain elements such as uranium, thorium, radium etc. have a property of spontaneously emitting invisible, highly penetrating an... 1
- What is meant by radioactivity? Elements with a high atomic number such as uranium, thorium, radium have a property of spontaneously emitting invisible, high penetrating an... 1
- Match the pairs Saturated brine a. sodium metal free Group A Group B 1. Saturated brine c. crystallization of salt 2. Fused salt a. sodium metal free 3. CaOCl₂ d. oxidation of colour 4. NaHCO₃... 1