Activity 2.1 NCERT Chapter 2 Metals and Non Metals
Indicator Acid Base Red litmus No Change Blue Blue Litmus Red No change Phenolphthalein Colourless Pink Methyl Orange Pink Yellow whether a substance is acidic or basic by Indictors are substance which change colour in acidic or basic media. Activity 2.2 There are some substances whose odour changes in in acidic or basic media. These are called olfactory indicators. Like onion vanilla, onion and clove. These changes smell in basic solution. Activity 2.3 Take about 5 mL of dilute sulphuric acid in a test tube and add few pieces of zinc granules to it. => You will observe bubbles of hydrogen gas on the surface of zinc granules. Zn + H2SO4 -- >. ZnSO4 + H2 => Pass the Hydrogen gas through the soap solution. Bubbles formed in the soap solution as Hydrogen gas it does not get dissolved in it. Take a burning candle near a gas filled bubble. Candle burn with pop sound. The metal combines with the acid and forms a compound called a salt. Read full post NCERT Activity 2.1 to 2.14
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Activity 1.1
Clean a magnesium ribbon by rubbing it with sandpaper to remove layer of carbonate and oxide. Burn it using a spirit lamp you get white ash of MgO. Mg (s) + O2(g) à MgO(s) => Magnesium ribbon burn with dazzling light and white powder of MgO is formed which is basic in nature It is an example of combination reaction in which single compound break into two or more substance. Activity 1.2 (Experiment): Take lead nitrate solution in a test tube. Add potassium iodide solution to this. => Yellow precipitate PbI2 is formed. Substance Insoluble in water is called precipitate. Pb(NO3)2 (aq) + 2KI à PbI2(s) (¯) + 2 KNO3 (aq) This is an example of precipitation reaction . This is an example of Double decomposition reaction in which there is exchange of radicals. Activity 1:3 (Experiment): Take a few zinc granules in a conical flask or a test tube. Add dilute hydrochloric acid or sulphuric acid to this. => The bubble of hydrogen gas is observed. The temperature of flask increases due to release of heat energy. Zn(s) + HCl(l) --à ZnCl2 (aq) + H2 ( ) This is called Exothermic reaction as there is release of heat . This is an example of Single displacement reaction in which more reactive element displace less reactive element from compound. Read full post NCERT Activity Activity 3.1 Page No. 37
Take samples of iron, copper, aluminium and magnesium. Note the appearance of each sample. They have a shining surface. Clean the surface of each sample by rubbing them with sand paper and note their appearance again. They become more shiny. => Freshly cut Metal have shiny surface Activity 3.2 Page No. 37 Take small pieces of iron, copper, aluminium, and magnesium. Try to cut these metals with a sharp knife and note your observations. They are very hard to cut. Hold a piece of sodium metal with a pair of tongs and try to cut it with a knife. Sodium can be cut easily with knife. Hence K and Na are soft metal cut with knife Activity 3.3 Page No. 38 Take pieces of iron, zinc, lead and copper try to strike it four or five times with a hammer. These metals are beaten into thin sheet on hammering. This property of metal is called malleability and metals are called malleable. Activity 3.4 Page No. 38 Take some metals such as iron, copper, aluminium, lead, etc. Which of the above metals are also available in the form of wires? Read full paper Read full post |
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