Water (H2O); Origin of Life By Mohammad Kamruzzamil Mojumder Contents Profile of water Physical properties of water Chemical aspects Chemical properties Reactions of water Importance in daily life Aspects as an energy resource Profile Water is a liquid at standard ambient temperature and pressure but it often coexists on earth with its solid state‚ Ice and gaseous state ‚steam (water vapor). It is a polar solvent but generally a weak electrical conductor and 65% of Human body weight is
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bus 9.2 – Production of Materials: Δ. Construct word and balanced formulae equations of all chemical reactions as they are encountered in this module: • Basic reactions to remember: – Acid reactions: ▪ acid + base [pic] salt + water HCl(aq) + NaOH(aq) [pic]NaCl(s) + H2O(l) ▪ acid + metal [pic] salt + hydrogen gas HCl(aq) + Mg(s)[pic]MgCl2(s) + H2 (g) ▪ acid + carbonate [pic] salt + carbon dioxide gas + water HCl(aq) + CaCO3(s)[pic] CaCl(s) + CO2(g) + H2O
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香港考試及評核局 HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITY 香港中學文憑考試 HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION 練習卷 PRACTICE PAPER 化學 試卷一 CHEMISTRY PAPER 1 評卷參考 MARKING SCHEME (2012年2月22日修訂稿) (updated as at 22 Feb 2012) Hong Kong Examinations and Assessment Authority All Rights Reserved 2012 PP-DSE-CHEM 1–1 權版留保 局核評及試考港香 © 。旨之巧技用運與力能解理重着試考違有亦 ，難解及對應懂學，習學善改生學助無既，度態習學種這。吞生剝 活，記死背硬，案答準標為視考參卷評將應不生學。用之考參生學 和師教供，寫編而卷習練科本為專局核評及試考港香乃考參卷評本 This marking scheme has been prepared by the Hong Kong
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CHEMISTRY (Theory) Time allowed : 3 hours General Instructions: (i) All questions are compulsory. Maximum Marks : 70 (ii) Marks for each question are indicated against it. (iii) Question numbers 1 to 8 are very short-answer questions and carry 1 mark each. (iv) Question numbers 9 to 18 are short-answer questions and carry 2 marks each. (v) Question numbers 19 to 27 are also short-answer questions and carry 3 marks each. (vi) Question numbers 28 to 30 are long-answer questions and carry 5 marks
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Safety of lithium-ion batteries June 2013 The European Association for Advanced Rechargeable Batteries Safety of Lithium-ion batteries Foreword This publication is prepared to provide information regarding the subject matter covered. The document has been prepared with the information available at the time of its publication. It is communicated with the understanding that the authors are not engaged in rendering legal or other professional services on issues covered by this report
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ConstruCtion microcontroller-based Ultrasonic distance meter and receiver)‚ current buffer ULN2003‚ operational amplifier LM324‚ inverter here are several ways to measCD4049‚ four 7-segment displays‚ five ure distance without contact. transistors and some discreet comOne way is to use ultrasonic ponents. The ultrasonic transmitterwaves at 40 kHz for distance measurereceiver pair is shown in Fig. 1. ment. Ultrasonic transducers measure Ultrasonic generators use piezothe amount of time
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Solder (/ˈsoʊldə/‚[1] /ˈsɒldə/[1] or in USA /ˈsɒdər/[2]) is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece(s). Soft solder is typically thought of when solder or soldering is mentioned‚ with a typical melting range of 90 to 450 °C (190 to 840 °F).[3] It is commonly used in electronics‚ plumbing‚ and assembly of sheet metal parts. Manual soldering uses a soldering iron or soldering gun.Alloys that melt between 180 and 190 °C (360
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Edexel IGCSE Chemistry Revision Notes IGCSE Chemistry Triple Award Revision Guide Topic Introduction to chemistry Atomic Structure Structure and Bonding – Ionic Bonding Structure and Bonding – Covalent and Metallic Bonding Organic Chemistry - Alkanes Organic Chemistry – Alkenes / Addition Polymerisation Organic Chemistry – Alcohols / Condensation Polymerisation Calculations Periodic Table Reactivity Series and Metal Extraction Electrolysis Energetics Acids‚ Bases‚ Salts and Neutralisation Preparing
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Applications of Colloids | Colloids play a very important role in nature‚ in our daily life and in industry. Some of the important applications of colloids are discussed below. 1. Food stuffs and medicines: Many of our food stuffs are colloidal in nature. Milk‚ butter‚ whipped cream‚ fruit jellies‚ ice cream‚ bread etc. are all colloidal in nature. For example‚ milk is an emulsion of butter fat in water‚ stabilized by milk protein (casein). Ice cream is a dispersion of colloidal ice particles
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Chemical decomposition can be defined as the separation of chemical compounds into smaller‚ simpler compounds (New World Encyclopedia‚ 2009). It is often considered an undesirable outcome of a chemical reaction. Radiation‚ humidity‚ heat‚ and acidity affect the stability of chemical compounds. Molecules‚ when put under harsh environmental conditions may break up into smaller particles. Decomposition can also be defined as the breakdown of one phase into two or more phases. Thermal‚ electrolytic‚
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