Chapter 9, Problem 9.2YT

Interpretation Introduction

Interpretation:

Arrows indicating the energy barriers of the exergonic reaction in Figure 9-1a and the endergonic reaction in Figure 9-1b are to be drawn. The two reactions are to be compared assuming the same energy scale.

Concept introduction:

The energy barrier to a reaction of an elementary step is the difference in the energies of the reactant and the transition state of that reaction or elementary step. The transition state is an excited state, and therefore, has a higher energy than the reactant(s). Therefore, the activation energy for a reaction or an elementary step is always positive.

The transtion state simulates the reactant in an exergonic reaction, while in an endergonic reaction, it mirror of the product.