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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An investigation on the activation energy for the iodine clock reaction Introduction: The iodine clock reaction is a presentation of chemical kinetics‚ which are the elements that affect the rate of chemical reactions. When the two colorless solutions are incorporated together‚ no reaction can be spotted. But after a short period of time‚ the solution turns into a dark blue solution. The term rate of reaction is stated as the decrease in the concentration of one of the reactions or the increase
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any way as a set of instructions. Clock reactions If you choose a project that explores the kinetics of a chemical reaction you will need a way of measuring the rate of the reaction. Clock reactions provide an interesting way of doing this for some systems. In a typical reaction the first part of a graph showing the concentration of product against time is approximately a straight line (see Figure 1). If you choose any value of concentration that lies on this straight line (say c1) the initial
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changing concentration: iodine clock reaction. Abstract This is an experiment to show the Iodine Clock Reaction. To create a chemical reaction to see how long it takes for solution to change to a dark blue Color. When changing the concentration of the iodide (K1) and adding distill water to make it up to 5cm³ each time. This is to see if the reaction takes less with less concentration or faster with more concentration added to the peroxodisulphatee. So with the solution made with more concentration
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Module 3 Accounting Adjustments and Constructing Financial Statements DISCUSSION QUESTIONS Q3-1. The fiscal year is the annual accounting period that a firm adopts. A firm that uses December 31 as its year-end is on a calendar-year basis. Traditionally‚ fiscal years that end in January through the end of May‚ are labeled as the prior calendar year. For example‚ a fiscal year ending January 31‚ 2010 would be labeled fiscal 2009 because the bulk of the operations occurred in calendar 2009
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HOMEWORK #3 Due Monday July 2‚ 2012 1 James Bond (90 kg)‚ outfitted with perfectly matching skis and skiware‚ is at the top of a steep slope that a secret spy like him can easily handle. He lets himself go from rest and smoothly slides down the h = 15 m high hill. A big parking lot lies at the bottom of the hill. Since the parking area has been cleared of snow‚ the friction between the ground and the skis brings our hero to a halt at point D‚ located at a distance d = 12 m from point C. The
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Chemical Kinetics: The Iodine-Clock Reaction: S2O82−(aq) + 2 I−(aq) → I2(aq) + 2 SO42−(aq) To measure the rate of this reaction we must measure the rate of concentration change of one of the reactants or products. Here‚ it is convenient to carry out a clock reaction involving the product I2. To do this‚ you will include (to the reacting S2O82− and I−) i) a small (but accurately known) amount of sodium thiosulfate‚ Na2S2O3‚ and ii) some starch indicator. The added Na2S2O3 does not interfere with
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Examples are: (a) Payment of an accounts payable. (b) Collection of an accounts receivable from a customer. (c) Transfer of an accounts payable to a note payable. 2. Transactions (a)‚ (b)‚ (d) are considered business transactions and are recorded in the accounting records because a change in assets‚ liabilities‚ or owners’/stockholders’ equity has been effected as a result of a transfer of values from one party to another. Transactions (c) and (e) are not business transactions because a transfer
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62 Iodine test for starch Amount of starch remaining Enzyme activity level Dark blue-black All None (0) Blue Most Low (1) Light brown Some Moderate (2) Gold None High (3) Part 1: Effect of Enzyme Concentration 1. Label five test tubes 1-5. Place 4 mL of 1 % starch in each of the first four test tubes. Place 4 mL of amylase solution in the fifth tube. Place all of the tubes in the 37°C water bath for 5 minutes. Obtain 5 clean droppers and label them 1-5. (To avoid contamination of these solutions‚ you
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Chapter 3 - Claudia’s Story : Green Pyjamas Claudia starts telling her story to the other children: Claudia’s parents quarrel a lot until her father decides to take his things and move away to his mother’s house. One night‚ there was a flood of phone calls‚ and for the first time‚ Claudia hears the name Stella‚ her dad’s new girlfriend. After that night‚ Claudia’s dad dare not visit nor come near the house anymore‚ but only talks to Claudia over the phone. On Boxing Day‚ Claudia meets Stella
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