what is the rate law of S2O8^2- + 3I-
--> 2SO4^2- + I3-
The rate law for a chemical reaction describes the relationship between the rate of the reaction and the concentrations of the reactants. To determine the rate law for the given reaction:
1. Start by setting up a series of experiments where the initial concentrations of the reactants are varied. The rate of the reaction can be determined by measuring the change in concentration of any of the reactants or products over time.
2. Once you have collected the data, compare the rates of the reaction in each experiment. Look for trends or patterns in the rates that correspond to changes in the concentrations of the reactants.
3. In this reaction, the reactants are S2O8^2- and I-. The products are 2SO4^2- and I3-. The balanced equation shows that the stoichiometric coefficient for S2O8^2- is 1, and for I- it is 3.
4. Based on your observations from the experiments and the stoichiometric coefficients, you can propose a possible rate law. In this case, since the rate of the reaction seems to depend on the concentration of both S2O8^2- and I-, the proposed rate law is:
Rate = k[S2O8^2-]^a[I-]^b
"k" represents the rate constant, and "a" and "b" are the reaction orders with respect to S2O8^2- and I-, respectively.
5. Finally, you need to determine the values of "a" and "b" by using the experimental data. This can be achieved by selecting two experiments where the concentration of one reactant is doubled while keeping the concentration of the other reactant constant, and observe the effect on the reaction rate. The exponent for the reactant whose concentration change resulted in a proportional change in the reaction rate will be the order of that reactant.
By following these steps and analyzing the data from relevant experiments, you can determine the rate law for the given reaction.