Chemical Kinetics Lab

Chemical Kinetics Lab - increasingly longer amounts of time...

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Kinetics of an Iodine Clock Reaction February 16, 2008 Introduction In this lab, we analyzed chemical kinetics, which is the study of the rates at which chemical reactions proceed. We found experimentally that the rate is proportional to the concentrations of the reactants. The expression Rate=k[A] x [B] y is called the rate law. The exponents x and y are called the orders of the reaction and k is the specific rate constant for the reaction. The order can only be determined experimentally, which we did by running several experiments using different concentrations of the reactant in question. Chemical Responsibility Many of the chemicals we work with do not have health hazards, except for ammonium persulfate, which is a strong oxidizer. They are to be disposed of in the waste bucket set up for the lab. Report Sheet (attached) Sample Calculations Discussion As we decreased the concentration of I - in the solution, the reactions took
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Unformatted text preview: increasingly longer amounts of time to complete. At 22 degrees Celsius, the reaction times were 31 seconds for 0.04 M, 46 seconds for 0.03 M, 73 seconds for 0.02 M and 137 seconds for 0.01 M. Our graph revealed that the reaction was first order. We then lowered the temperature of the solutions to 12 degrees Celsius and timed the reaction. For the 0.04 M reaction at the decreased temperature, it took 129 seconds for the reaction to complete, four times slower than run #1. Post Lab Questions (attached) Conclusion In this exercise, we confirmed that the dependence of the overall rate of reaction is first order in iodide ion concentration. We also saw that increasing temperature increases the reaction rate, while decreasing temperature decreases the reaction rate. A graph of 1/t versus [I-] was a straight line, showing the two are proportional....
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This note was uploaded on 08/15/2008 for the course CHM U215 taught by Professor Lui during the Spring '08 term at Northeastern.

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