Final answer:
At very high temperatures, bimolecular reaction rates can deviate from the typical Arrhenius temperature dependence due to factors such as changes in the reaction mechanism or the role of collision frequency. For example, the NO₂(g) + CO(g) reaction at high temperatures follows a first-order rate law with respect to both NO₂ and CO, suggesting a bimolecular mechanism. This indicates that factors other than just an increase in collision rate may affect the reaction rate at high temperatures.
Step-by-step explanation:
Non-Arrhenius temperature dependence of bimolecular reaction rates at very high temperatures
At very high temperatures, bimolecular reaction rates can deviate from the typical Arrhenius temperature dependence. While Arrhenius behavior predicts that reaction rates increase with temperature, deviations can occur due to factors such as changes in the reaction mechanism or the role of collision frequency.
For example, for the NO₂(g) + CO(g) reaction at temperatures above 225 °C, the rate law is first order with respect to NO₂ and CO, indicating a bimolecular mechanism. This suggests that factors other than just an increase in collision rate may affect the reaction rate at high temperatures.
Keywords: bimolecular reaction rates, temperature dependence, Arrhenius law