Rates of Chemical Reactions

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RATES OF CHEMICAL REACTIONS REACTION ORDER FOR IODATE ION OBJECTIVE: To determine the order of a KIO3-NaHSO3 reaction with respect to the iodate ion. To determine a difference on the rate of the reaction when the solution is 10oC higher than a room temperature. BACKGROUND: The rate of a chemical reaction is the speed at which reactants are converted to products. Some reactions are very fast and some are very slow. In order for a chemical reaction to occur, particles of the reactants involved must collide with one another at the correct angle and with the correct amount of energy. The factors, which affect the rate of a reaction, are the surface area, nature of the reactants, concentration, temperature, and catalysts. In this experiment, two solutions will be mixed, and the completion of the reaction will be marked by a color change. One solution contains the iodate ion (IO3-). The other contains the hydrogen sulfite ion (HSO3-) and soluble starch. The net ionic equation is as follows: 5 HSO3- + 2 IO3- I2 + 5 SO4-2 + H2O +3 H+ It should be expected that the rate of this reaction will depend on the concentration of the biosulfite ion and the iodate ion. However, is the reaction fifth order with respect to the biosulfite ion? It seems unlikely that five biosulfite ions would be able to simultaneously collide with two iodate ions. It woul be more likely that the reaction proceeds in a series of elementary reactions. In this lab, the order of the reaction will be determined with respect to the iodate ions. This information would help in de... ... middle of paper ... ... with the concentration of the reactants. The difference between concentration 2 and 1 is two times smaller then the difference between rate 2 and 1. Doubling the concentration of KIO3 increases the rate by factor of 4, so reaction is a second order. The second objective was to determine a difference on the rate of the reaction when the solution is 10oC higher than a room temperature. As it was expected, an increase in temperature led to a faster rate for a chemical reaction. Rate of the reaction at 38 oC is 239.16 times faster then the reaction at room temperature. This result proves that increasing the temperature causes the particles move faster. When particles move faster, more collisions occur and the collisions are more violent. That is why the higher temperature increased an experimental reaction rate from 5.63472E-5 M/sec to 0.013475894 M/sec.

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