21. This notion does not follow from elemental thermochemistry or chemical kinetics and was introduced by Hammett intuitively. 22. Does your question deals with chemical kinetics ? 23. The concepts of chemical kinetics are applied in many disciplines, such as chemical engineering, enzymology and environmental engineering. 24. Stiff problems are ubiquitous in chemical kinetics , control theory, solid mechanics, weather forecasting, biology, plasma physics, and electronics. 25. For instance, a cellular network can be modelled mathematically using methods coming from chemical kinetics and control theory. 26. Which reactions do occur and how fast is the subject of chemical kinetics , another branch of physical chemistry. 27. Late in his career, his scientific interests moved from physical chemistry ( particularly chemical kinetics ) to neurobiology. 28. The molar mass distribution of a polymer sample depends on factors such as chemical kinetics and work-up procedure. 29. His work on chemical kinetics and chemical engineering led him to define and study differential equations on graphs. 30. The chemical kinetics due to collisional coupling of states B and C and vibrational relaxation are not well known.