CHEM3412 Synthesis of a Porphyrin Porphyrins are hetereonuclear‚ macrocyclic compounds that play an important role in living organisms. Examples include the non-protein heme portion of hemoglobin in animals whereby the lone pairs on nitrogen can bind to the oxygen-carrying iron. In plants‚ chlorophyll uses the vast conjugation to allow absorption of light for photosynthesis. The characteristic colors of porphyrins is also due to the conjugation. An examination of the porphyrin structure
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Write your name here Surname Other names Centre Number Candidate Number Edexcel IGCSE Chemistry Unit: 4CH0 Science (Double Award) 4SC0 Paper: 1C Wednesday 25 May 2011 – Morning Time: 2 hours Paper Reference 4CH0/1C 4SC0/1C You must have: Ruler Candidates may use a calculator. Total Marks Instructions black ink or • Usein the boxesball-point pen. page with your name‚ Fill at the top of this • centre number and candidate number. all • Answer
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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 and Analysing Salts Rates Equilibria
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litmus turns red and then is bleached white. (ii) White precipitate. (i) Non-metal‚ is acid in aqueous solution and a powerful oxidising agent (ii) It forms a small amount of chloride ion in water‚ so gives a positive result for the chloride test. Bromine Br2 (l or aq) A dark red liquid - orange-brown fumes‚ yellow-orange aqueous solution. The other common orange-brown gas is nitrogen dioxide (i) Shake with a liquid alkene. (ii) Mix with silver nitrate solution. (ii) Decolourised. See alkene test
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is the nitronium ion which is generated from nitric acid by protonation and loss of water‚ using sulfuric acid as the dehydrating agents. Data: Weight (grams) Beaker 39.1 grams Beaker + Crystals 41.9 grams Weight of Crystals (Prior to Addition of Ethanol) 2.8 grams Figure 1: This table illustrates the weight of the crystals that were formed before the ethanol was added. 2.8 grams x 5= 14 mL - This is the amount of ethanol that is needed to just dissolve the bromonitrobenzenes at
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unsaturated hydrocarbon with a double or triple carbon-carbon bond. | Bubble gas through‚ or add liquid to‚ a solution of bromine in hexane or water. | The orange/brown bromine rapidly decolourises‚ as a saturated colourless organic bromo-compound is formed. | R2C=CR2 + Br2 ==> BrR2C-CR2BrRCCR + 2Br2 ==> Br2RC-CRBr2R = H‚ alkyl or arylSaturated alkanes give no fast reaction with bromine. | Hydroxy group R-OH in alcohols and phenols (in ’dry’ conditions*) The first 3 tests (i) - (iii) given on the right
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source is needed to reverse the flow‚ and only one container is needed. 2. What is the measured value of Ecell for each cell and its relevance to the EOred for the iron half-cell and halogen half-cells? The measured value of Ecell for the zinc‚ iron‚ bromine‚ and iodine half-cells were -0.71‚ 0.61‚ 0.40‚ and 0.51 respectively. The standard cell potential is the difference between the standard electrode potential of the cathode (reduction) half-cell and the standard electrode potential of the anode (oxidation)
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Chapters 11 12 Periodic Table Name __________________ ( ) Class __________ Date _________ History of the Periodic Table Russian chemist Dmitri Ivanovich Mendeleev 1834-1907 Arranged elements in order of increasing atomic masses Elements with similar chemical properties fall into the same vertical column Such an arrangement is the Periodic Table The Periodic Table The Periodic Table is a list of elements arranged in order of ______________ _____________ (__________) ____________. Groups
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materials reached the stratosphere the were acted on by ultraviolet radiation and broke down releasing chlorine and bromine into the ozone layer. The ozone layer is the earth’s ultraviolet shield. The chemistry is such that the chlorine and bromine attack the ozone‚ reducing it to ordinary oxygen which as no shielding effect from UV-B. The complex chemical reactions allow the chlorine and bromine to interact again and again with ozone molecules‚ until they eventually leave the ozone layer bonded to some
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Hence‚ these elements do not easily gain electrons because of the weak attraction to the nucleus. Moreover‚ as you move down groups 6 and 7‚ reactivity decreases. For example‚ chlorine was the most reactive than bromine and iodine‚ which makes sense because chlorine is placed above bromine on the periodic
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