Enzymes are nature's catalysts, mediating chemical processes in living systems. The study of enzyme function and mechanism includes defining the maximum catalytic rate and affinity for substrate/s (among other factors), referred to as enzyme kinetics. Enzyme kinetics is a staple of biochemistry curricula and other disciplines, from molecular and…

Describes a simple redox reaction that occurs between potassium permanganate and oxalic acid that can be used to prepare an interesting disappearing ink for demonstrating kinetics for introductory chemistry. Discusses laboratory procedures and factors that influence disappearance times. (CW)

Defines the rate-controlling step in contrast to the terms rate determining and rate limiting. Discusses the usefulness of this concept in describing kinetic isotope effects, consecutive reactions, chain reactions, and enzyme-catalyzed reactions. (CW)

Describes a kinetic and mechanistic investigation of ascorbic acid by a substitution-inert complex in acidic medium suitable for the undergraduate level. Discusses obtaining the second order rate constant for the rate determining step at a given temperature and comparison with the value predicted on the basis of the Marcus cross-relation. (CW)

Discusses the mechanism and the change of pH during the reaction. Notes that a dramatic rise in pH occurs when the reaction nears completion. Evaluates theories by other authors. (MVL)

Considers variables which affect the acquisition of the kinetic theory of heat by children who hold alternative viewpoints. Suggests that the articulation of different viewpoints in no way hinders the acquisition of the desired conceptual framework. Emphasizes the benefit to low-reasoning students in particular. (CW)

Presented are several simple kinetic systems together with the spreadsheets used to solve them. A set of exercises in chemical kinetics appropriate for an introductory course in physical chemistry is given. Error propagation calculations with experimental data are illustrated. (CW)

Describes three case studies of the use of the Learning in Science Project (Energy) in New Zealand. Themes discussed include systems undergoing change, defining initial and final conditions, energy as a nonmaterial factor of change, forms of energy and conservation of energy. Mentions other issues and research. (CW)