Many advanced high school and college chemistry students perform an experiment known as the "iodine-clock" reaction‚ in which hydrogen peroxide reacts with iodide to form iodine‚ and the iodine subsequently reacts with thiosulfate ion until the thiosulfate has been consumed. At that point‚ the reaction solutions turn blue in the presence of starch. The experiment helps students understand the fundamentals of chemical kinetics --- the speeds at which reactions take place. 1. Activation Energy
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Title : Investigation of Action of Saliva and 3M HCl in Two Carbohydrates Solutions. Objective : To investigate the action of saliva and 3M hydrochloric acid in two carbohydrate solution. Result : Table 1 : The presence of starch and reducing sugar in the solution Observation Conclusion Solution A Benedict’s test : The transparent blue solution turns into opaque brick-red precipitate Iodine’s test : The clear colourless solution turns into transparent yellowish-brown
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FORM 4G ELECTROLYSIS WORKSHEET TERM 3 2010-2011 1.Figure 1 below is a diagram of the apparatus used in the electrolysis of fused sodium bromide. Figure 1 a)Write the formulae for the ions present in the fused sodium bromide. b)Write an ionic equation to represent the reaction taking place at the positive and negative electrodes. c)When the heat source was removed‚ the crucible cooled and the lamp went out. Explain why the lamp went out when the crucible cooled. d)At the end of the experiment
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Guide Questions Experiment 1 Calibration of the calorimeter: 1. Give the net ionic thermochemical equation of the reaction used to calibrate the calorimeter. a. Is the reaction endothermic or exothermic? b. Which is the limiting reactant? c. How much (in moles) limiting reactant was used? d. How much heat was generated (or absorbed) by the reaction? 2. Relate the sign of the ΔT to the ΔH of the reaction used for calibration. 3. What is the heat capacity of the calorimeter? Relate
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THERMOCHENISTRY Index 1.0 Introduction | | | | | | | | 1 | 2.0 Enthalpy Changes | | | | | | | 2‚3 | 2.1 The Standard Conditions For Calculating Enthalpy Changes | | | | 3.0 Hess’s Law | | | | | | | | 4‚5 | 3.1 The Applications of Hess’s Law | | | | | | 4.0 Standard Molar Enthalpy Change of Formation‚ ΔHof | | | | 6‚7 | 4.1 The Stability of A Compound | | | | | | | 4.2 Using ΔHof
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with the sample under controlled conditions. The quantity of oxidant consumed is expressed in terms of its oxygen equivalence. Because of its unique chemical properties‚ the dichromate ion (Cr2O72–) is the specified oxidant in Methods Section 5220B‚ Section 5220C‚ and Section 5220D; it is reduced to the chromic ion (Cr3+) in these tests. Both organic and inorganic components of a sample are subject to oxidation‚ but in most cases the organic component predominates and is of the greater interest. If
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MECHANISM OF AQUEOUS HUMOR FORMATION There is a constant flow of aqueous humor through the anterior segment of the eye. The aqueous is formed by the ciliary process and flows from the posterior chamber to anterior chamber through the pupil and exits the eye at the angle. The secretion of aqueous humor generates the intraocular pressure required for an optically efficient globe. The flow of aqueous provides nutrition for the avascular ocular tissues that it bathes‚ the posterior surface of the
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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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1 OCTOBER 5 2013 QUALITATIVE TESTS FOR SOME CATIONS II I. Introduction Qualitative analysis schemes are often based on selective precipitation of different cations. By carefully selecting reagents and conditions for reactions‚ groups of ions can be separated on the basis of their reactivity and the solubility of their salts. This enables the experimenter to use simple techniques with standard laboratory equipment‚ as well as to learn some descriptive chemistry. Cations are Alkali and Alkaline
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w w ap eP m e tr .X w om .c s er UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education 0620/12 CHEMISTRY Paper 1 Multiple Choice May/June 2010 45 Minutes Additional Materials: *8778752636* Multiple Choice Answer Sheet Soft clean eraser Soft pencil (type B or HB is recommended) READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples‚ paper clips‚ highlighters‚ glue or correction
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