Chemical Kinetics 1 Overview Getting Started Techniques Procedure FAQ Full Lab Manual Introduction & Goals Chemistry & Background Key Questions Prelab Problems Safety Procedure In Your Write-up Experiments Index ChemLab Home		Prelab Problems 1. The rate of a chemical reaction can be expressed in terms of the change in concentration of any reactant or product with time. Thus, for the hypothetical reaction: A + 2B C, the rate of reaction can be expressed in terms of -d[A]/dt or -d[B]/dt or +d[C]/dt. If we wish to equate the rates of disappearance or appearance of different reactants or products in the same reaction, the stoichiometric coefficients of the balanced chemical equation must be taken into account. Thus for the example above, we write since each mole of A that disappears takes with it 2 mol of B and produces 1 mol of C. For the net reaction of iodine and cyclohexanone, write an equation relating the rates at which the following concentrations change: [cyclohexanone], [I2 + I3-], [iodinated cyclohexanone]. 2. Assuming that the reaction is first order with respect to each reactant, arrange reaction runs (i)-(v) in order of expected increasing rate. 3. Assume that run (i) was carried out and the following data were obtained: t/min A565 5 0.25 10 0.18 15 0.11 20 0.06 Plot the data in the three functional forms corresponding to zero, first, and second order reactions. What is the reaction order with respect to iodine + triiodide, according to these data? The applet Kinetics Plot, on the ChemLab website, can help you complete this problem. Sketch the graphs that the applet plots in your notebook, in addition to stating the reaction order.
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