= Chemical kinetics
{wiki}
<Chemical kinetics> studies how quickly <chemical reactions> proceed and how their <reaction rates> depend on composition and conditions. It connects a measured change in <concentration> to a <rate law>, then uses a <rate equation> to predict future <concentrations>. This makes it useful for choosing how long to wait for conversion and for testing a proposed <reaction mechanism>. Changing <temperature>, <reactant> <concentrations>, or the presence of a <catalyst> can change <reaction rates>; see https://openstax.org/books/chemistry-2e/pages/12-2-factors-affecting-reaction-rates[Flowers et al., Chemistry 2e, §12.2: factors affecting reaction rates].
<Chemical equilibrium> specifies the eventual balance under given constraints; <chemical kinetics> determines how rapidly it is approached. At fixed <temperature> and <pressure>, a decrease in <Gibbs free energy> favours conversion but does not guarantee a fast <chemical reaction>: reaching a <transition state> can require crossing a substantial barrier. Thus a mixture can change imperceptibly over an observation period without being at <chemical equilibrium>. The distinction separates which direction is favoured from how long conversion takes. See <Chemistry 2e by Paul Flowers and others/12.5 Collision Theory> (§12.5: collision theory and reaction barriers) and https://openstax.org/books/chemistry-2e/pages/16-1-spontaneity[Chemistry 2e, §16.1: spontaneity and speed].
Back to article page
