Reaction Kinetics, at a glance

Orders come from rates or an explicit elementary mechanism, not overall coefficients. A zero-order concentration-time plot is straight; first order has constant successive half-lives. Derive k units from the measured rate units and overall order.

Concentration changes collision frequency. Temperature changes collision frequency and the energetic fraction, increasing k. A catalyst changes the pathway and lowers the barrier while leaving the same-temperature energy distribution and equilibrium constant unchanged. Enzymes add active-site specificity and temperature/pH sensitivity.