The purpose of this experiment is to determine the rate law for the reaction of iodine with acetone using the method of initial rates. The initial rate of each of the reactions is determined by the amount of time that is required for the color of iodine to disappear. The rate law of the reaction depends on the concentration of one or more reactants and is the relationship between the “rate of the reaction and the concentration of the reactant.” [ (Tro) ] The rate law is defined by Equation 1 for the following reaction, aA + bB→ cC + dD
Where, m is the reaction order with respect to A, and n is the reaction order with respect to B. The overall order is simply the sum of the exponents. Because there is no simple way to determine the rate law for a given reaction, the initial rate method is used to determine the rate. To use the initial rate method, concentrations of each reactant are varied independently leaving the concentrations of the remaining reactants constant. This method allows us to determine the dependence of the rate of reaction upon a particular reactant. If the concentration of one reactant is doubled and the rate of the reaction also doubles, the reaction must be first order with respect to that reactant. If the concentration of the reactant is doubled and the rate of the reaction quadruples, the reaction must be second order with respect to that reactant. If there is no correlation between reactant concentration and rate of reaction, then the reaction is zero order with respect to that reactant. If the order cannot be determined this way, any two initial concentrations and the corresponding initial rates can be substituted into Equation 2, and the order of a particular reactant can be determined:
Equation 2: rate 2rate 1= k[A]2nk[A]1n
In order to correct for the dilution of the initial concentrations of each reactant, Equation 3 was used where:
Equation 3 :CiVi=CfVf, and C=...