Chemistry II Week 4 Notes
Chemistry II Week 4 Notes CHEM 1120
University of Memphis
Popular in GENERAL CHEMISTRY II
verified elite notetaker
Popular in Chemistry
This 2 page Class Notes was uploaded by Annika Coley on Friday February 19, 2016. The Class Notes belongs to CHEM 1120 at University of Memphis taught by Dr. Brewster in Spring 2016. Since its upload, it has received 17 views. For similar materials see GENERAL CHEMISTRY II in Chemistry at University of Memphis.
Reviews for Chemistry II Week 4 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/19/16
Chemistry Notes II – Week 4 Ch 15 Integrated rate law o Ln[A]=-kt+ln[A] intital o For first order reactions o Straight line with a negative slope Half-life of first order reactions (t ) 1/2 o Length of time for the concentration to decrease by half o Is a constant o .693/k or ln(2)/k Second order integrated rate law o 1/[A]=kt+1/[A] intial o Straight line on a graph with a positive slope Zero order integrated rate law o –[A]=-kt+[A] intial o Straight line with negative slope Effect of temperature on reaction rates o Change in temperature changes the constant k Arrhenius equation o K=Ae (-Ea/or ln(k)=(-Ea/R)(1/t)+ln(A) T is temperature in kelvin R is the gas constant Ea is the activation energy in Joules A is a constant o Two point form Ln(k2/k1)=(-Ea/R)(1/T 21/T1) Activation energy o Amount of energy required to convert reactants into the activated complex or into the transition state o Not just the energy to break bonds – it is also the sum of all energies that need to be overcome o As temperature increases, the molecules that will have enough energy will increase Collision theory of kinetics o Molecules have to collide to react o 10 collisions per second o Reaction depends on energy and orientation Effective collision o Makes activated complex or transition state Reaction mechanism o Series of reactions that lead to forming your product o Need to know the rate law to understand the reaction mechanisms Reaction Equation: H +22ICl → 2HCl + I 2 Step 1: H + ICl → HCl + HI 2 Step 2: HI + ICl → HCl + I2 Elementary steps of the mechanism HI is made and consumed during the reaction so it does not appear in the reaction equation o It is an intermediate Molecularity o Number of reactant particles in an elementary step Unimolecular- one particle Bimolecular- two particles Termolecular- three particles Rate-determining step o The step that occurs slower than the other steps in the mechanism o Overall rate of the reaction cannot be faster than this step o Determines rate law of overall reaction Validating a mechanism o Elementary steps must sum to produce the overall balanced chemical equation o Rate law predicted by the rate determining step must be consistent with experimentally observed rate law Mechanisms with a fast initial step o The rate limiting step may contain intermediates o Can substitute into the rate law of the rate-determining step to get a rate law of just reactants Catalyst o Changes the rate of a reaction o Can be a positive or negative catalyst o Generally lowers the activation energy of a reaction o Changes the reaction mechanism Homogeneous catalyst o The catalyst is in the same phase as the particles reacting o Catalyst could be another liquid in solution Heterogeneous catalyst o Catalyst is in a different phase o A solid among gases Enzymes o Biological catalysts
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'