CBSE ADDA

X Class 10 NCERT Activity Explanation Class 10 Metals and Non Metals 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

NCERT Activity Chapter 02 Acid Bases and Salt Class 10 Chemistry Activity 2.1 Indicator Acid Base Red litmus No Change Blue Blue Litmus Red No change Phenolphthalein Colourless Pink Methyl Orange Pink   Yellow 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

X NCERT ACTIVITIES Class 10 Chemical Reactions and Equations Activity 1.1 (Experiment): 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) + O 2 (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 PbI 2 is formed. Substance Insoluble in water is called precipitate. Pb(NO 3 ) 2   (aq)     +      2KI    à PbI 2 (s) ( ¯ )    +  2 KNO 3   (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

​Class 10 Sample Paper Board Exam 2020-21 10th Science 2020 CBSE Practice Paper -1 Download File 10th Science 2020 CBSE Practice Paper -2 Download File 10th Science 2020 CBSE Practice Paper -3 Download File 10th Science 2020 CBSE Practice Paper -4 Download File 10th Science 2020 CBSE Practice Paper -5 Download File 10th Science 2020 CBSE Practice Paper Solution(1-5) Download File See all sample Papers  Visit

Class 09 Atoms and Molecules Numerical Problem based on Law of chemical Combination Law of conservation of mass Law of constant proportion Empirical formula 1. If 10 grams of CaCO 3 on heating gave 4.4g of CO 2 and 5.6g of CaO, show that these observations are in agreement with the law of conservation of mass.(Based on Law of conservation of mass) Solution:  Mass of the reactants = 10g ;  Mass of the products = 4.4 + 6.6g = 10g Since the mass of the reactants is equal to the mass of the products, the observations are in agreement with the law of conservation of mass. 2. 1.375 g of cupric oxide was reduced by heating and the weight of copper that remained was 1.098g.  In another experiment 1.179 g of copper was dissolved in nitric acid and the resulting copper nitrate was converted into cupric oxide by ignition . The weight of cupric oxide formed was 1.476 g. which law of chemical combinations does this data state? Solution: in first experiment: Copper oxide = 1.375g ;   Coppe