Catalysis

Catalysis (/kəˈtælᵻsᵻs/) is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst (/ˈkætəlᵻst/). With a catalyst, reactions occur faster and require less activation energy. Because catalysts are not consumed in the catalyzed reaction, they can continue to catalyze the reaction of further quantities of reactant. Often only tiny amounts are required.

Technical perspective

In the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations. The effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons (which reduce the catalytic activity) or promoters (which increase the activity). The opposite of a catalyst, a substance that reduces the rate of a reaction, is an inhibitor.

Catalyzed reactions have a lower activation energy (rate-limiting free energy of activation) than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature and for the same reactant concentrations. However, the detailed mechanics of catalysis is complex. Catalysts may affect the reaction environment favorably, or bind to the reagents to polarize bonds, e.g. acid catalysts for reactions of carbonyl compounds, or form specific intermediates that are not produced naturally, such as osmate esters in osmium tetroxide-catalyzed dihydroxylation of alkenes, or cause dissociation of reagents to reactive forms, such as chemisorbed hydrogen in catalytic hydrogenation.

Catalyst (disambiguation)

A catalyst is a substance which increases the rate of a chemical reaction.

Catalyst may also refer to:

Buildings

Economics and finance

Events

Media and entertainment

Games

Literature and publications

Catalyst (TV program)

Catalyst is the ABC's primary science journalism television series and the only science show on primetime television in Australia. Launched in 2001, it replaced Quantum, which had ceased the previous year. Catalyst is regularly broadcast on ABC 1 at 8:00 pm on Tuesdays and at 11:30 am Saturdays. Also repeated on ABC News 24 on Saturdays at 4:30 pm.

Catalyst celebrated its tenth year of production in 2010.

Description

The show broadcasts stories on scientific themes, and in particular significant recent developments and discoveries. It focuses primarily on stories relevant to Australia, but the series covers international developments as well. It attempts to convey information in a way that is not only accurate but also interesting and informative to the general population, often discussing the ethical, political, and other implications of scientific discoveries and research as well as the discoveries themselves.

The show's website describes it as follows:

Each week Catalyst brings you stories from Australia and around the world.