Here is cbse 2007 question paper of science: CBSE X SCIENCE AND TECHNOLOGY (Theory) 2007 (OUTSIDE DELHI) Time allowed: 2 hours 15 mins; Maximum Marks: 100 General Instructions: | 1) | The question paper comprises of two sections A and B. You are to attempt both sections. | 2) | You are advised to attempt all the questions of Section A and Section B separately. | 3) | All questions are compulsory. | 4) | There is no overall choice. However‚ internal choice has been provided in some questions
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Table 8.1- Combustion of magnesium ribbon Observations Reaction was exothermic; magnesium ribbon burned and was glowing a bright white color when ignited. Reactants: Mg and O2 Products: MgO Balanced chemical equation 2Mg + O2 2MgO Table 8.2- Combustion of heptane Observations When holding test tube inverted over heptane flame‚ condensation formed against top walls of the test tube. When the burning splint was added the walls of the test tube became less foggy from the condensation
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carbon residue‚ but also silicon dioxide‚ calcium oxide and traces of heavy metals. If inhaled these can pose significant health risks. The silicon dioxide in the fly ash alone can cause lesions‚ scarring and inflammation of the lungs. 2) Sulfur Dioxide. Sulfur
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Research 1. Assess evidence‚ which indicates increases in atmospheric concentration of oxides of sulfur and nitrogen. Thorough collection of data‚ surveys‚ and tests from the 1950’s indicate a rising trend in atmospheric concentrations of oxides of sulfur and nitrogen. An enhancement in funding‚ technological and information resources‚ has led to wider and more detailed analyses of oxides of sulfur and nitrogen concentrations‚ and as the diagrams indicate (see diagrams) there is a clear rise in
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gas called sulfur dioxide or SO2 for short. This toxic component is found in products made of plastic and certain preservatives found on dried fruits and nuts. Sulfur Dioxide as a vapor is released into the air then falls to the ground in the rain. This is known as acid rain. Acid rain has two indirect effects on our ecosystems. The first‚ acid rain slowly destroys our forests and plant-life. When acid rain falls‚ it seeps into the soil around trees and plants. Over time‚ the sulfur dioxide dissolves
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CUSTOMISED FERTILIZERS Rural Marketing Submitted By Kiran S. Ahirrao Roll No. 1006 Customized Fertilizers 1. What is Customized Fertilizer? Ans: Customised Fertilizers are combination of micro nutrients like sulphur‚ zinc‚ boron added to the key items such as urea and diammonium phosphate (DAP) and potash‚ in a proportion that suits specific crops and soil patterns. A fertilizer formulated according to specifications that are furnished by/for a consumer prior to mixing‚ usually based
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Presence of Insecticides & Pesticides in Fruits & Vegetables SCHOOL : K .V N T P C CHEMISTRY PROJECT REPORT STUDY THE PRESENCE OF INSECTICIDES AND PESTICIDES IB FRUITS AND VEGETABLES Name : Class : Reg. No : Examiner Teacher-in charge. CERTIFICATE This is to certify that the project was done by …………………………… Reg. No ……………….. Is in partial fulfillment of Chemistry Practical Examinations
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MATERIALS : METALS AND NON-METALS Y Iron Coal ou are familiar with a number of materials like iron‚ aluminium‚ copper‚ etc. Some materials have been given in Table 4.1. Table 4.1 : Appearance and Hardness of materials Object /Material Appearance Hardness (Shiny/Dull) (Very hard/ Not very hard) similar change if we try to beat a wood log ? Let us find out. Activity 4.1 Take a small iron nail‚ a coal piece‚ a piece of thick aluminium wire and a pencil lead. Beat the iron nail with
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Introduction This experiment was designed to discover the how paper and other materials burned. The research question is: “What added material makes paper burn fastest?” My hypothesis was that gasoline would burn up the fastest. The experiment includes soaking toilet paper squares in various materials and burning them to see which burns the best. Research Paper itself burns well‚ that is a common known fact. Gasoline‚ rubbing alcohol‚ and petroleum jelly also are widely known as highly flammable
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HOW FAST ARE CHEMICAL REACTIONS? THEORY The study of reaction rates‚ how fast or how slow a reaction takes place‚ is known as chemical kinetics. The rate of chemical reactions varies greatly. Some reactions‚ such as the explosion of an atom bomb are uncontrollable. Reactions like the decay of radioactive carbon (14C) are so slow that it takes centuries to see any noticeable change. Between the two extremes are reactions that can be measured in the laboratory. There are several factors that
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