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 in the concentration of
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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 the rate of above reaction‚ but
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hydrochloric acid. The reaction occurs via nucleophilic substitution‚ in which a nucleophile replaces the leaving group in the substrate. In this case‚ the hydroxyl group of t-butyl alcohol is replaced by a chlorine atom. The reaction proceeds via Sn1mechanism. The second part of the experiment consisted of purification of t-butyl chloride using the distillation process. A nucleophile is any neutral or uncharged molecule with an unshared pair of electrons. In the substitution reaction‚ the nucleophile
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Introduction What is chemical change? Chemical change is the alteration of a substance into one or more different substances with different properties (also called chemical reaction). The four different types of chemial reations are synthesis‚ decomposition‚ single displacement‚ and double displacement. Synthesis is when atoms and/or molecules combine to form larger molecules. Decomposition is when a large molecules are split into elements or smaller molecules. Single Displacement has an element
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There are eight types of chemical reactions. These eight reactions are Decomposition‚ Composition‚ Acid/Base‚ Synthesis‚ Single-Replacement‚ Double-Replacement‚ Precipitation‚ and Redox. Though these eight could be referred to as the same due to them being chemical reactions. They are actually very different. An example of this difference is Decomposition and Synthesis. Decomposition is when a compound is broken into smaller chemical species while a Synthesis reaction is two or more chemical species
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determine whether or not a chemical reaction occurred after the mixing of various chemicals. The evolution of a gas‚ the formation of precipitation‚ and the change of temperature or color are all indicative of a chemical reaction. It was assumed that a reaction did not take place if the mixture of chemicals exhibited none of these characteristics. Several precipitation‚ complex-ion formation‚ redox‚ and acid-base reactions were performed. Redox: Decomposition Reactions In a 13 x 100 mm test tube‚ 2 mL
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concentration of a species can affect reaction rate in the determination of rate law and rate constant. 2. To determine how temperature affects reaction rate. Introduction Chemical kinetics deals with the speed‚ or rate‚ of a reaction and the mechanism by which the reaction occurs. We can think of the rate as the number of events per unit time. The rate at which you drive (your speed) is the number of miles you drive in an hour (mi/hr). For a chemical reaction the rate is the number of moles that
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Observations | Reaction Type | Complete and Balance | 1. When heated in oxygen‚ magnesium gives off a bright white flame. | combination reaction | 2Mg + O2-----> 2MgO | 2. Bubbling and fizzing occurs; the zinc appears to “dissolve” and what appears to be “steam” comes off out of container. | single-displacement reaction | Zn + 2 HCl (aq) --> ZnCl2(aq) + H2(g) | 3. Black smoke occurs | decomposition reactions | 2 (H2O2)(aq) MnO2 2 (H2O) + (O2) | 4. reddish-brown deposit
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Endothermic and Exothermic reactions A chemical reaction is a process in which one or more substances are chemically changed into one or more new substances. A chemical reaction may involve the motion of electrons in the forming and breaking of chemical bonds. Therefore when a chemical reaction takes place‚ energy is transferred to‚ or from‚ the environment. A Chemical reaction can either be exothermic or endothermic. Exothermic Reactions During an Exothermic Reaction a transfer of energy to the
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In the lab testing the heat of a reaction to understand changes in enthalpy in an exothermic reaction‚ the group hypothesized that if the amount of reactant is changed then the amount of heat produced (exothermic) will increase. This hypothesis was supported through the data as each of the six trials produced heat and the larger the piece of magnesium the larger the change in heat was. In the first trial the group had .085 grams of Mg and after being placed in 3 ml of 21.8℃ HCl the temperature of
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