What is Chemical kinetics?
[[File:Molecular-collisions.jpg|thumb|right|250px|With a higher concentration, molecules will hit each other more easily and so the speed of the reaction will be bigger]] '''Chemical kinetics''', also called '''reaction kinetics''', is the branch of physical chemistry connected with study of how fast [[chemical reaction]]s go. This includes studying how different conditions such as [[temperature]], [[pressure]] or [[solvent]] used, affect the speed of a reaction. Chemical kinetics can also be used to find out about [[reaction mechanism]]s and [[transition state]]s. The basic idea of chemical kinetics is called collision theory. This states that for a reaction to happen, the [[molecule]]s must hit each other. Ways of increasing the speed of the reaction must therefore increase the number of hits. This can be done in many ways. With experiments it is possible to calculate reaction rates from which you can get [[Rate law|rate laws]] and [[rate constants]]. A rate law is a mathematical expression with which you can calculate the speed of a reaction given the [[concentration]] of the reagents. == Order of a reaction == the equilibrium is dynamic in nature There are many types of rate laws, but the most common are: *zero-order reaction: the speed does not depend on the concentration *first-order reaction: the speed depends on the concentration of only one reactant *second-order reaction: the speed depends on the concentration of two reactants, or on the concentration of one reactant squared. From this data, it is possible to think about the mechanism of the reaction. If it is second-order, for example, then it is likely that both [[molecule]]s in the reaction are coming together during the [[rate-determining step]]. This is the most difficult step in the mechanism to go through, because it has the highest [[activation energy]]. {{Reaction mechanisms}} [[Category:Chemical kinetics]]