L3_115b08

L3_115b08 - L3: Chemical Kinetics and Mechanisms of...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
L3: Chemical Kinetics and Mechanisms of Chemical Rxns Concepts and definitions: Rate of reaction: consistent definition for reactants and products Differential rate law: Rate dependence on reactant (initial) concentration aA + bB cC + dD changes of concentrations of reactants and products are related by the balanced equation. dt B d b dt A d a dt D d d dt C d c R ] [ 1 ] [ 1 ] [ 1 ] [ 1 = = = = n m B A k dt A d a R ] [ ] [ ] [ 1 = = Order of the reaction: m -order in A ; n -order in B Overall order: m + n (small numbers, not necessarily integers) m,n must be determined experimetally; they are NOT a and b m+n+ . .. = 1: 1st order reaction m+n+ . .. = 2: 2nd order reaction, etc. k = rate constant (at constant temp.)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Measuring rates: iodine clock reaction 2IO 3 - (aq) + 5SO 3 2- +2H + -> I 2 + 5SO 4 2- +H 2 O R ~ [IO 3 - ] n R ~ 1/time Thus, 1/time ~ [IO 3 - ] n 15 15 0.067 12.5 21 0.048 10 16 0.063 7.5 35 0.029 5 50 0.02 [IO 3 - ] 0 time 1/t Iodine clock 0 0.02 0.04 0.06 0.08 0.1 0 5 10 15 20 C0 1/t Series1 Insert link: Iodine clock reaction http://chemed.chem.purdue.edu/demos/main_pages/22.4.html 2008 data x x x x x x
Background image of page 2
Units of R (always ) : dt A d a R ] [ 1 = Units: aA + bB -> cC + dD 1 1 ] [ = s L mol R Units of k : n m B A k R ] [ ] [ = n m B A R k ] [ ] [ = mol*L -1 * s -1 0 L 2 *mol -2 * s -1 3 L*mol -1 * s -1 2 s -1 1 [k] m+n Units of k vary with overall order of the reaction
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2. Integrated Rate Law: Dependence of [ C ] on t
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 07/22/2008 for the course CHEM 115b taught by Professor Reisler during the Spring '08 term at USC.

Page1 / 19

L3_115b08 - L3: Chemical Kinetics and Mechanisms of...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online