Chemical Reactions and Equations Chemical Reaction: The transformation of chemical substance into another chemical substance is known as Chemical Reaction. For example: rusting of iron‚ setting of milk into curd‚ digestion of food‚ respiration‚ etc. In chemical reaction new substance is formed which is completely different in properties from the original substance‚ so in a chemical reaction chemical change takes place. Following are the signs of chemical reaction: (a) Change of state of substance
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The Earth’s atmosphere has changed over billions of years‚ but for the past 200 million years it has been much as it is today. We are‚ however‚ causing our atmosphere to change by human activity. Burning fossil fuels and deforestation are two examples of human effect on the environment. Composition of the Earth’s atmosphere The composition of air You need to know the proportions of the main gases in the atmosphere. The Earth’s atmosphere has remained much the same for the past 200 million years
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Observations: Part I: Reaction between iron and oxygen Appearance of steel wool after 20 minutes From (relatively) shiny metal strips to not-so-shiny strips that are stained with dark‚ reddish-brown stuff. Part II: Decomposition of hydrogen peroxide Appearance of potato and hydrogen peroxide combination: Lots of white‚ foamy bubbles around the potato slices. Day 2 Observations: Part III: Reaction between zinc and acetic acid Appearance of penny in vinegar after
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chalk + limestone (from calcium carbonate) - metamorphic rock has crystals - formed by heat + pressure on sedimentary rock - contains interlocking crystals - eg marble (from limestone or chalk) quarrying limestone - produces local jobs in rural areas + improves economy - quarries can be landscaped after - used 4 making cement (heated w powdered clay) - used 4 making concrete (mix cement + sand + gravel + water) - used 4 making glass (heated w sodium carbonate + sand) - all used to construct
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Extraction of Aluminium Aluminium ore is called bauxite. Bauxite contains aluminium oxide‚ water‚ iron oxide and other impurities. The purified dry ore‚ called alumina‚ is aluminium oxide (Al2O3). The alumina must be molten for electrolysis to work‚ since the ions are not free to move in the solid state. Unfortunately‚ alumina has a high melting point (2040 °C) and it is not practical to do electrolysis at such a high temperature. In the middle of the nineteenth century it was found that alumina
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This page intentionally left blank Copyright © 2008‚ New Age International (P) Ltd.‚ Publishers Published by New Age International (P) Ltd.‚ Publishers All rights reserved. No part of this ebook may be reproduced in any form‚ by photostat‚ microfilm‚ xerography‚ or any other means‚ or incorporated into any information retrieval system‚ electronic or mechanical‚ without the written permission of the publisher. All inquiries should be emailed to rights@newagepublishers.com ISBN (13) : 978-81-224-2652-6
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CHEMICAL REACTION (SYNTHESIS REACTION‚ DECOMPOSITION AND SINGLE REAPLACEMENT REACTION) Purpose : 1. To identify the chemical changes 2. To observe the effect of temperature of a chemical reaction. Theoritical basic : A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically‚ chemical reactions encompass changes that strictly involve the motion of electrons in the forming and breaking of chemical bonds between
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Calcium hypochlorite is a chemical compound with formula Ca(ClO)2. It is widely used for water treatment and as a bleaching agent. This chemical is considered to be relatively stable and has greater available chlorine than sodium hypochlorite (liquid bleach). Preparation It is manufactured by the calcium process: ~\mathrm{2Cl_2 + 2Ca(OH)_2\longrightarrow \ Ca(OCl)_2 + CaCl_2 + 2H_2O}. "Bleaching powder" is a mixture of calcium hypochlorite (Ca(OCl)2) and the basic chloride CaCl2‚ H2O with
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the mass of the reaction mixture would NOT decrease as the reaction proceeds. 10 F It is difficult to measure the volume of water produced from the reaction between oxalate ions and permanganate ions in aqueous solution. 1 11 T During the decomposition of hydrogen peroxide solution‚ oxygen gas is formed. 2H2O2(aq) 2H2O(l) + O2(g) If the reaction vessel is a closed system‚ the pressure inside the vessel will increase. The progress of the reaction can be followed by measuring the pressure inside
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Chapter 1 Chemical Reactions and Equations Q.1. Why should magnesium ribbon be cleaned before burning in air ? Ans: Magnesium ribbon is a very reactive metal. When stored it reacts with oxygen to form a layer of magnesium oxide on its surface. This layer of magnesium oxide being a stable compound prevents further reaction of magnesium with oxygen. The magnesium is cleaned before burning in air to remove this layer so that the metal can be exposed to air properly. Q.2. Write the balanced
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