University:
Georgia Southern University
Course:
CHEM 1310 | Comprehensive General Chemistry
Academic year:

2024
Views:

352

Pages:

2
Author:

Jalen W.

A KINETICS REACTION SUMMARY TABLE ORDER Zero Rate change vs. Concentration Rate does not change with change in reactant concentration Rate Law Rate constant, k units Integrated Rate Law Second Rate depends on reactant concentration Doubling the reactant concentration quadruples the reaction rate 2 Rate = k Rate = k[A] Mol/L sec Sec or 1/sec L/mol sec [A] = - kt + [A]o ln [A] = -kt + ln[A]o 1/[A] = kt + 1/[A]o t1/2=[A]o / 2k Half life First Rate = k [A] -1 t1/2 = 0.693 / k t1/2 = 1 / k [A]o Straight line plot A] versus t ln[A] versus t 1/[A] versus t Relationship: k to slope Slope = -k Slope = -k Slope = +k Illustrations of order plots: ZERO ORDER [A] FIRST ORDER ln [A] TIME SECOND ORDER 1/[A] TIME TIME Notes • The above summary is for rate laws that depend ONLY on the concentration of the reactants. • There are two types of rate laws. • One is the rate as a FUNCTION of the reactant concentration. • The second type is the integrated rate law that relates how the reactant's concentration DEPENDS on time. • The orders of the reactants and the value of the rate constant, is obtained from experimental data involving the initial rates of reactions at various initial concentrations of the reaction's reactants. • The rate laws for reactions that have more than one reactant can be determined by choosing conditions ( i.e. pseudo first order reactions) where only one reactant varies in a given experiment with the others held constant: Rate = k [A]n [B]m [C]p Rate = k' [A]n • Where: k' is equal to k[B]om [C]op and [B]om >>[A]o & [C]op >> [A]o o The reaction order n is obtained by determining which plot gives a straight line. k' is derived from the plot's slope. o The other orders, m & p, and the rate constant k are found by determining the k' at various concentrations of B and C.