chem Iodine-Clock Reaction

chem Iodine-Clock Reaction - Iodine-Clock Reaction Lab...

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Iodine-Clock Reaction Lab
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Objective: To study the effect of changes in concentration on the rate of a chemical reaction. Theory: Chemistry can be defined as the science of matter, and its interaction with other matter. In this experiment, the effect on concentration on the rate of a chemical reaction is observed. A chemical reaction is defined as a change in the arrangement of atoms or molecules to yield substances of different composition and properties. In this particular case, different concentrations of potassium iodate solution are reacted with starch-sulfite solution to observe the effect of changes in concentration on the chemical reaction rate. A chemical reaction can be described using a chemical equation. A chemical equation is a symbolic representation of the relationship between the reactants and products of a chemical reaction. A net ionic equation, an equation that shows only ions that undergo change during a chemical reaction, simplifies a chemical equation to simply what is reacting, by providing a net reaction. In this particular lab, the net equation is represented by the following: 2IO 3 - + 5SO 3 2- → I 2 + 5SO 4 2- + H 2 O In some reactions, when a reaction takes place, usually there is a physical change, or something able to be observed. In this reaction, however, the change is not as evident. Therefore, an indicator of starch must be used. The starch will react with I 2 when I 2 is formed, indicating the end of the chemical reaction. When I 2 and starch react, they form a blue complex, physically indicating that the reaction is completed. The rates of reaction are dependent upon several factors, such as concentration of reactants, temperature, surface area, action of catalysts, and the nature of the reactants. This lab primarily focuses on the effect of the concentration of the reactants on the rate of the reaction. Concentration is a term used by scientists to designate the amount of solute dissolved in a given quantity of solvent or solution. The greater the amount of solute dissolved in a certain amount of solvent, the more concentrated the resulting solution. The concentration of solutions can be expressed quantitatively through several ways, with the two primary ways being molarity and molality. Molarity, symbol M , expresses the concentration of a solution as the number of moles of solute in a liter of solution. Molality, symbol m , expresses the concentration of a solution as the number of moles of solute in a kilogram of solvent. When an ionic compound dissolves, it dissociates into its component parts, or its individual ion. Each individual ion retains the concentration of the original compound, but once dissolved in a liquid, changes the overall concentration. For example, a 1.0 M solution of NaCl is 1.0 M in Na + and Cl - ions. In solution, it would be 2.0 M. Similarly, a 1.0 M solution of Na 2 SO 4 is 2.0 M in Na + and 1.0
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chem Iodine-Clock Reaction - Iodine-Clock Reaction Lab...

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