Order of reaction with respect to I^- and S2O8^2-?

[member 392791]

What is the reaction order supposed to be for this reaction of each one? I got 1 for I- and 2 for S2O8, but I think it should be 1 for both of them. Can anyone confirm?? These were the numbers I found experimentally

The reason for concern here is that I did a ratio because I used twice as much s2o8 for reaction 1, then twice as much for 2, etc. The ratio should be r1/r2 = 2^x, r2/r3 = 2^x, etc. The problem is that r1/r2 gave x=3.8, when the other two gave 1.6 and 1.2, and we are supposed to find the average to get the reaction order. The average rounds off to 2, but that is because of the major outlier of 3.8. I checked and to find R you use 6.3x10^-4 / time of reaction to get the R's. I looked at the class data and everyone got the same reaction times as me, so either we all got it wrong or it is a 2nd order reaction.

The I- gave 0.8, 1.2, and 1.0 which gave a nice y=1 for the average, so its a first order. There is no cause for alarm because they are all close to each other. Would I use the same number for the s2o8 as i-, the 6.3x10^-4/time? that number came from the formula

 

[Zefram]

for the rate law

it is important to carefully analyze and interpret experimental data to determine the correct reaction order for a given reaction. In this case, it appears that there may be some discrepancies in the data and calculations, leading to confusion about the reaction order.

Firstly, it is important to note that the reaction order is not determined by the amount of reactants used, but rather by the rate of the reaction as the concentration of reactants changes. Therefore, using a ratio of reactant amounts may not accurately reflect the reaction order.

Additionally, the formula for determining the reaction order is not simply the ratio of the reactant concentrations. It involves plotting a graph of the reaction rate versus the concentration of each reactant, and determining the slope of the line. The reaction order is then equal to the exponent of the concentration term in the rate law equation.

In this case, it appears that the experimental data for the reaction rate versus the concentration of S2O8 may not be consistent with a first-order reaction. It is possible that there were errors in measuring the reaction times or concentrations, leading to the outlier of 3.8 in the ratio calculation. It may be necessary to repeat the experiment and carefully double-check all measurements to ensure accuracy.

As for the question of using the same number for S2O8 as I-, it is important to note that each reactant may have a different rate constant, which would affect the overall reaction rate and the reaction order. Therefore, it is not appropriate to use the same number for both reactants without further analysis.

In conclusion, it is important to carefully analyze experimental data and use proper methods to determine the reaction order for a given reaction. If there are discrepancies or outliers in the data, it may be necessary to repeat the experiment and ensure accuracy in measurements. Additionally, each reactant may have a different rate constant and should not be assumed to have the same reaction order.