# Units second-order rate constant

We have seen that 10" M s is about the fastest second-order rate constant that we might expect to measure this corresponds to a lifetime of about 10 " s at unit reactant concentration. Yet there is evidence, discussed by Grunwald, that certain proton transfers have lifetimes of the order 10 s. These ultrafast reactions are believed to take place via quantum mechanical tunneling through the energy barrier. This phenomenon will only be significant for very small particles, such as protons and electrons. [c.136]

To analyze the rate constant problem we start with Eq. (5-43), k = (kT/h)K. The term (kT/h) has the unit second", so consistency is achieved if the concentration units of k and are identical. As before, we pass to pure numbers, writing (for a second-order rate constant) [c.212]

For a first-order reaction, therefore, a plot of In Ca (or log Ca) vs. / is linear, and the first-order rate constant can be obtained from the slope. A first-order rate constant has the dimension time , the usual unit being second. [c.18]

Chemical kinetics the study of reaction rates in solution (1990) -- [ c.20 ]