In order to determine which reaction would affect the rate of CH 4 oxidation the most, and therefore be the rate limiting step of the overall reaction, "brute force" sensitivity analyses were performed on each metal surface, increasing the rate of each surface reaction by 1%, one at a time. Sensitivity was measured by comparing the perturbed result of interest to the original result of interest (e.g. conversions, yields, and selectivities, maximum rate of CH 4 conversion, and distance to 50% CH 4 conversion), seen in Equation ( ):