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9th CBSE Science Chap 3 Atoms and Molecules Self study Questions

Solved problems:Class 9 _Atoms and Molecules  1. Q. 5 g of calcium combine with 2 g of oxygen to form a compound. Find the molecular formula of the compound. (Atomic mass of Ca = 40 u; O = 16 u)  Ans. Number of moles in 5g of calcium = mass / molar mass    =5 /40    =  0.125  Number of moles in 2g of oxygen = mass / molar mass         =  (2 / 16)  =  0.125 Now we will calculate the simplest ratio of the element by dividing the number of moles of each element by the smallest value.  Since number of moles of each element is 0.125, therefore calcium and oxygen are present in a ratio of 1 : 1. Thus the empirical formula of the compound is CaO. For calculating the molecular formula, we need the molecular mass of the compound. However, because a compound with the formula CaO is known, Therefore the molecular formula of the compound is CaO. . Q. (i) Name the body which approves the nomenclature of elements and compounds.

Floatation_Class-9 important solved Questions from previous year CBSE Board Paper

Fully Solved Questions from previous year board Paper Question: 1. What causes buoyant force (or up thrust) on a boat? Answer: Buoyant force is due to volume of boat and density of water. Question: 2. what is the cause of buoyant force? Answer: : The pressure difference on lower part and upper part of a body cause of buoyant force . Question: 3. An Object of volume V is immersed in a liquid of density P. Calculate the magnitude of buoyant force acting on the object due to the liquid Answer: Vd g Question: 4. why does a block of wood held under water rise to the surface when released? Answer: This happens because as upward force is greater than the weight. Question: 5. What happens to the buoyant force as more and more volume of a solid object is immersed in a liquid. When does the buoyant force become maximum? Answer: The buoyant force exerted by a fluid is equal to the weight of fluid displaced. Therefore the buoyant force increases as more and more vol

Solved SA-1 Sample papers for class 9 [Maths and Science] New

Download and starts practicing sample papers for class 9 [Maths and Science] New Class 9 Science S A - 1 Fully Solved Sample Question papers 9th science sa-1 toppers fully solved Sample paper-1 Download File 9th science sa-1 toppers fully solved Sample paper-2 Download File 9th science sa-1 toppers fully solved Sample paper-3 Download File 9th science sa-1 toppers fully solved Sample paper-4 Download File 9th science sa-1 toppers fully solved Sample paper-5 Download File 9th science sa-1 toppers fully solved Sample paper-6 Download File 9th science sa-1 toppers fully solved Sample paper-7 Download File Class 9 Science S A - 1 Fully Solved Original Question papers 9th science SA - 1 fully solved Question paper -1 Download File 9th science SA - 1 fully solved Question paper -2 Download File 9th science SA - 1 fully solved Question paper -3 Download File Class 9 Mathematics S A - 1 Fully Solved Sample Question papers Class 9 Maths SA-1 fully solved paper with Marking Scheme Class 9

Improvement in Food Resources class 9 fully solved question from CBSE Exam paper

CBSE solved ,unsolved test papers,Notes, Assignments and Guess Papers : First Term: Improvement in Food Resources. Plant and animal breeding and selection for quality improvement and management; use of fertilizers, manures; protection from pests and diseases; organic farming. SA-I (2013) TLPEK7V 1. Mention two climatic conditions essential for different crops for growth and completion of their life cycle. 1 Ans: Temperature and photoperiods. 2. “Green Revolution of 1960 is a boon by itself”. List three steps that may be initiated to increase crop production 3 Ans: The major groups of activities for improving crop yields can be classified as: (a) Crop variety improvement (b)Crop production improvement (c) Crop protection management. 3. In what ways internal parasites like worms and flukes and external parasites cause harm to the cattle’s. 3 Ans: External parasite – Skin diseases; worms – affect stomach and intestine; Flukes – damage liver 4. Explain the mean

Basic Science Class 8 Solution by Jsunil

We are providing you scanned copy of exercise so that you can check your study chapters are: 1. Food production     2.The cell  3. Micro organism   4. Reproduction  5. Synthetic Material 6. Metal and non metals  7.Combustion and Flame  8.Force and Pressure Some of them are here Basic Science Question Answer Class 8 Bharati Bhawan Publication  Class 8 Metal and Non Metal                             Download File Class 8 Combustion and Fuel                             Download File Class 8 Electricity and Lighting                         Download File Class 8 Microorganisms Friend and Foe            Download File Click on Link Searches related to basic science for class 8 simple science experiments for class 8 basic science for class 7 basic science for class 6 basic 8th grade science Class VIII Mathematics  [Click on links given below] VIII Algebra VIII Commercial Maths VIII Geometry & Mensuration   CBSE Class VIII Science Physics

SA-1 class 10 Sample Paper of Science Sept. 2015 New addition

U-Like CBSE CCE Sample Papers AS CBSE sample papers have many advantages. These papers give students an idea of the pattern of the paper and help them evaluate their preparedness for the exams. Understanding the CBSE marking scheme and the types of questions are two very big advantages as well. Fully solved paper by Jsunil Tutorial Class X Science SA-1 Solved Question paper 2014-1 Download File Class X Science SA-1 Solved Question paper 2014-2 Download File Class X Science SA-1 Solved Question paper 2014-3 Download File Class X Science SA-1 Solved Question paper 2014-4 Download File Class X Science SA-1 Solved Question paper 2014-5 Download File SA-1 class 10 Sample Paper of Science Sept. 2015 New addition class 10 Sample Paper Science Sept. 2015 -1 Download File class 10 Sample Paper Science Sept. 2015 -2 Download File class 10 Sample Paper Science Sept. 2015 -3 Download File class 10 Sample Paper Science Sept. 2015 -4 Download File class 10 Sample Paper Scienc

Class- (10)X-Mathematics : Summative Assessment I (SA - 1): Sample Question Paper with solution New

Class- (10)-Mathematics:  Summative Assessment I (SA -1): Sample Question Paper with solution New Fully solved Previous papers SA-I Class-X Maths-1 (Download) SA-I Class-X Maths-2(Download)   SA-I Class-X Maths-3(Download) SA-I Class-X Maths-4(Download) SA-I Class-X Maths-5(Download) SA-I Class-X Maths-6(Download)) class 10 Sample Paper of Mathematics Sept. 2015 Class 10 Mathematics 2015 Sample Paper - 01 Download File Class 10 Mathematics 2015 Sample Paper - 02 Download File Class 10 Mathematics 2015 Sample Paper - 03 Download File Class 10 Mathematics 2015 Sample Paper - 04 Download File Class 10 Mathematics 2015 Sample Paper - 05 Download File