time it takes for the cross on the bottom of the beaker while the reaction is recurring to disappear. As it can be seen in the graph‚ the higher the temperature the shorter the time is for the Sulphur to be created. If it is looked as one continuous line‚ the first part of the trend line shows a steep‚ straight and constant decrease; then the 2nd part is not as steep and has a more gradual decline. Moreover‚ it shows how a reaction at 20°C a slower time for the cross to disappear compared to 40°C
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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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PAHANG TRIAL 2009 EXAMINATION CHEMISTRY PAPER 2 MARKING SCHEMES SECTION A - Structural Questions: Question 1. (a) (i) The presence of isotopes 1M (ii) Let the abundance of 63X be a %. The % abundance of 65X. = ( 100 – a ) 1M Relative atomic mass = ( 62.93 x a) + ( 64.93 x ( 100 -a) ) 1M
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of chemistry that studies the energy and heat associated with chemical reactions and/or physical transformations. A reaction may release or absorb energy‚ and a phase may change‚ such as in melting and boiling. Thermochemistry focuses on these energy changes‚ particularly on the system ’s energy exchange with its surroundings. In combination with entropy determinations‚ it is used to predict whether a reaction is spontaneous or non-spontaneous‚ favourable or unfavourable. Chemical reactions can
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Coursework Plan |Coursework title-highlight key words | |How are the protagonists’ and the authors’ attitudes towards humanity highlighted and emphasized in the poems “Dulce et Decorum Est” and “Refugee Blues”. | | | |Main
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meant to supplement‚ not replace the laboratory manual. SN1 Reaction Notes Background and Application Substitution Nucleophilic First Order (SN1) reactions are one of the most common type of organic reactions. SN1 reactions can be used to make a wide variety of new compounds. In this experiment‚ t-amyl alcohol will be converted by a SN1 mechanism to 2-chloro-2-methylbutane. Safety Precautions Concentrated Hydrochloric Acid is 12M. It will cause visible destruction of tissue upon contact
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GCSE Physics Coursework - Resistance of a Wire Coursework Resistance of a Wire Task To investigate how the resistance of a wire is affected by the length of the wire. Theory What is resistance? Electricity is conducted through a conductor‚ in this case wire‚ by means of free electrons. The number of free electrons depends on the material and more free electrons means a better conductor‚ i.e. it has less resistance. For example‚ gold has more free electrons than
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Practice Set- Balancing Reactions Section I - Place the appropriate coefficient on the line in front of each species to balance each equation and then under each equation identify the reaction type. 1. ____ Cu +_______Cl2 ® _________ CuCl 2. _____ H2O ® ______ H2 + _______ O2 3.______ KBr + _______ AgNO3 ® ______ KNO3 + _______ AgBr 4. ______ CH4 + _______O2 ® ________ CO2 + ________ H2O 5._______ Zn + _______ HCl ® ________ H2 + _______ ZnCl2 6. _____Fe + ______ H2O ® _______ Fe3O4 + _______
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Chemical reactions can happen slowly or fast. The speed of the reaction rate can be changed. Some of the factors that can affect the reaction rate are surface area‚ temperature‚ and concentration and pressure. Surface area is the exposed‚ outer layer of a solid. Increased surface area increases reaction rate because more particles on the surface of a solid come in contact with the particles of another substance. For example‚ if you place a donut stick into water‚ the donut will react slowly with
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There are three reactions in the iodine clock reaction. The first reaction is IO3-(aq) + 3 HSO3-3 SO4-(aq) + I-(aq)+ 3 H+(aq)‚ where the iodate ions become iodide ions1. The second reaction is 6 H+(aq) +IO3-(aq) + 5 I-(aq) 3 I2(aq) + 3 H2O(l) where the iodate ions become molecular iodine2. The third reaction involves molecular iodine becoming a dark blue starch;I2(aq) + starch blue-black complex3. These three reactions react in a sequence. In any reaction the concentration is exponentially related
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