[THC]

2 NO2 (g) + O3 (g) -> N2O5 (g) + O2 (g)

[NO2]/M   [O3]/M    v/M/s
0.0014     0.0025    4.8*10^-8
0.0021     0.0025    7.2*10^-8
0.0021     0.0050    1.4*10^-7

Find the reaction orders for NO2 and O3.


Is there a systematic approach to this? I think the data seems a bit odd - why is the concentration constant? By trial-and-error I found that n = 1 and m = 1 for v = k*[NO2]^n*[O3]^m where k is a constant, by finding k = v/([NO2]*[O3]) = constant. This cannot be the optimal solution
How do I solve this properly?

[enahs]

Between Trial 1 & 2. The concentration of O3 is constant, only the concentration of NO2 changes. How does the rate change between the two? This tells you the reaction order for NO2 because it is the only thing that changes.

Between trial 2 & 3. The concentration of NO2 is constant, only O3 changes. How does the rate change between these two? This tells you the reaction order for O3 because it is the only thing that changes.

It is not "trial and error", it is looking at the data and selectively picking which one tells you information.


http://www.chem.ufl.edu/~itl/2045/lectures/lec_l.html