kinetics

the study of the rates of chemical reaction and the steps by which they occur

collision theory

States that in order for a reaction to occur... 1. Particles must collide 2. Particles must collide in the correct orientation 3. Collision must be energetic enough to form products

effective collision

a collision in which the particles are sufficiently energetic and collide in the proper orientation

activation energy

the minimum amount of energy necessary for a chemical reaction to occur

activated complex

an unstable, intermediate substance that forms as the reactants transition into products; short lived and high energy

reaction rate

a measure of how quickly reactants change into products (amount concentration per second; moles per liter per hour)

catalyst

a substance that changes a reaction's rate without being consumed by the reaction (is neither a reactant nor a product)

homogeneous catalyst

catalyst in the same phase as the substances in the reaction

heterogeneous catalyst

catalyst in a different phase than the substances in the reaction

enzyme

naturally occurring biochemical catalyst

inhibitor

a substance that reduces the effectiveness of a catalyst, slowing its action

reaction mechanism

the series of steps that make up a chemical reaction

elementary step

an individual step in the reaction mechanism

rate-determining step / rate-limiting step

the slowest elementary step in the reaction mechanism which determines the rate of the reaction

complex reaction / net reaction

the elementary steps as a whole

intermediates

substances formed in one elementary step and consumed in the next; do not appear in the equation for the net reaction

reaction order

an indication of the effect that the concentration of a particular reactant has on the reaction rate

rate law

mathematical law relating the concentration of reactants to the rate of a reaction

general form of rate law

R = k [A]^m[B]^n

single-step reactions

an elementary reaction, as shown in its balanced chemical equation with no intermediates; rare situation where the coefficients equal the exponents