CH16_equilibria_1 - Chapter 16: Chemical Equilibria Brady &...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 16: Chemical  Equilibria th  edition
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 Dynamic Equilibrium in Chemical  Systems Chemical equilibrium exists when Reaction appears to stop  [ reactants products ] don't change over time Remain constant Equilibrium signified by double arrows ( or equal sign (=)
Background image of page 2
3 Dynamic Equilibrium Acetic acid + water at some initial  concentrations 
Background image of page 3

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

View Full DocumentRight Arrow Icon
4 Dynamic Equilibrium As H 3 O +  & AA -  form  Reverse rate Ions collide more frequently as [ions]  Eventually  rate forward  =  rate reverse Equilibrium  Almost all systems come to equilibrium Some systems equilibrium hard to detect  Essentially no reactants or no products  present
Background image of page 4
5 Concentration as Reaction Progresses N 2 O 4     2 NO 2    Initially  [N 2 O 4 ] [NO 2 ]  change relatively quickly  Eventually stop changing with time Equilibrium  is reached. (Fig. 16.1) [N 2 O 4 ] i Equilibrium Reached [NO 2 ] i
Background image of page 5

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

View Full DocumentRight Arrow Icon
6 Reaction Reversibility  Closed system Equilibrium  condition   can be  reached from  either direction Independent of  whether start with  “reactants” or  “products” N 2 O 4 2 NO 2
Background image of page 6
7 Closed System  Overall quantities  are fixed Whether start with  all reactant or all  product Always have same  composition at  equilibrium under  same conditions . N 2 O 4 2 NO 2
Background image of page 7

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

View Full DocumentRight Arrow Icon
8 For given overall system composition Always reach same equilibrium concentrations Whether equilibrium is approached from  forward  or  reverse  direction. N 2 O 4 2 NO 2 Reactants Products
Background image of page 8
9 Equilibrium Simple relationship among [ reactants [ products ] for any chemical system at  equilibrium Called =  mass action expression Derived from thermodynamics Forward reaction: A       B     Rate =  k f [A] Reverse reaction:  A       B      Rate =  k r [B] At equilibrium: A       B       k f [A] =  k r [B]   rate forward   rate reverse rearranging:  constant ] [ ] [ = = r f k k A B k f k r
Background image of page 9

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

View Full DocumentRight Arrow Icon
10 Ex:  H 2 ( g )  + I 2 ( g )    2HI ( g )    @ 440°C Exp’t  # Initial  Amts Equil’m  Amts Equil’m [M] I 1.00   mol  H 2 0.222  mol  H 2 0.0222  M  H 2 10  L 1.00   mol  I 2 0.222  mol  I 2 0.0222 
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/06/2008 for the course CHEM 1220 taught by Professor Meghee during the Spring '08 term at St. Johns Duplicate.

Page1 / 34

CH16_equilibria_1 - Chapter 16: Chemical Equilibria Brady &...

This preview shows document pages 1 - 11. Sign up to view the full document.

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