What is the major source of energy for dissociation reaction?
Answers
Answer:
The dissociation of water molecules into molecular dihydrogen (H2) and molecular dioxygen (O2) is a chemical reaction of great practical interest in terms of the energy transition and the so-called hydrogen economy. Depending on operating conditions, either liquid (Eq. 3.1) or gaseous (Eq. 3.2) water molecules can be split.
(3.1)
½
(3.2)
½
Besides considering the reaction stoichiometry (Lavoisier conservation law), it is also necessary to consider the energetics of the reaction. Using the absolute temperature (T) and pressure (P) as state variables, the energetics of the reaction is summarized by the Gibbs–Helmholtz equation:
(3.3)
The dissociation of water molecules over the temperature range (ambient to ~1000°C) and the pressure range (1–800 bar) of practical feasibility, and interest for the chemical industry, is an endergonic (nonspontaneous) process. The situation at 1 bar is summarized in Fig. 3.1.
