Agreement, Complement, and Disagreement to "Why Are Some Reactions Slower at Higher Temperatures?"

作者：Ge Yingbin^*

来源：Journal of Chemical Education, 2017, 94(6): 821-823.

DOI：10.1021/acs.jchemed.7b00208

• Upper-Division Undergraduate
• Physical Chemistry
• Computer-Based Learning Kinetics
• Kinetic-Molecular Theory
• Student-Centered Learning

In the article "Why Are Some Reactions Slower at Higher Temperatures?" published in this Journal, Revell and Williamson explained, from the enthalpic and entropic aspects, why an A + B -> P reaction may proceed more slowly at higher temperatures via an A + B <-> C -> P mechanism using the pre-equilibrium approximation. Their explanation is convincing but may be too abstract for undergraduate physical chemistry students to understand fully. In this communication, a numerical implementation and graphical demonstrations of their explanation are provided for students to use to "see" for themselves a negative activation energy. Although Revell and Williamson perfectly explained the negative temperature dependence of the A + B <-> C -> P reaction rate, great caution must be exercised when their explanation is applied to interstellar chemistry where the pre-equilibrium approximation may be invalid and statistical thermodynamics functions may be ill-defined.

• 出版日期2017-6