1 / 32

Chemical Equilibrium Chapter 18 Modern Chemistry

Chemical Equilibrium Chapter 18 Modern Chemistry. Sections 1 & 2 The Nature of Chemical Equilibrium Shifting Equilibrium. Section 18.2. Shifting Equilibrium. Seesaws and Equilibrium. LeChatelier’s Principle A play in one act. TEACHER: “Let’s put stress on the equilibrium!”

knox-rowe
Download Presentation

Chemical Equilibrium Chapter 18 Modern Chemistry

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ChemicalEquilibriumChapter 18 Modern Chemistry Sections 1 & 2 The Nature of Chemical Equilibrium Shifting Equilibrium Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  2. Section 18.2 Shifting Equilibrium Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  3. Seesaws and Equilibrium Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  4. LeChatelier’s PrincipleA play in one act. Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  5. TEACHER:“Let’s put stress on the equilibrium!” STUDENTS:“How?”(puzzled) TEACHER:“Change the T, P, or concentration.” LECHATELIER:“A new equilibrium will be attained.” STUDENTS:“How?”(amazed) TEACHER:“One of the reactions will go faster, for a while, to relieve the stress.” STUDENTS:“I understand.”(with confidence) Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  6. The End. Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  7. LeChatelier’s Principle Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  8. LeChatelier’s Principle • If a system at equilibrium is subjected to a stress, the equilibrium is shifted in the direction that tends to relieve the stress…and a new equilibrium is achieved. Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  9. How is a system “stressed”? • Changing the concentration • Adding a reactant or product • Removing a reactant or product • Changing the temperature. • Changing the pressure Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  10. Changes in Pressure • Affects only eq. with gases • Increasing the pressure favors the side with the fewest particles • Leading to a decrease in pressure • Decreasing the pressure favors the side with the most particles • Leading to an increase in pressure • If particle are equal, pressure has no effect. • Increasing pressure by adding a gas that is not a reactant or a product cannot affect the eq. Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  11. Balanced Equation • 2NO2 (g)  N2O4 (g) + Energy • O2 (g) + 2SO2 (g) + Energy  2SO3 (g) • N2 (g)+ 3 H2 (g) 2NH3 (g)+ Energy • 2HI(g)+ Energy  H2 (g)+I2 (g) • O2 (g) + N2 (g) 2NO2 (g) • Keq = 4.5 x 10-31 at 25 ° C • Keq = 6.7 x 10-10 at 627 °C Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  12. Complex Ions • Central Metal • Surrounded by ligands • Examples of ligands • H2O • NH3 • CN1- • Cl1- Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  13. Changes in Concentration • Increase the concentration of reactants • the forward reaction is favored • Increase the concentration of products • the reverse reaction is favored Up, Up and Away Take Away Towards Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  14. Complex Cu Ion System UP, UP AWAY [Cu(H2O)4 ] 2+ + 4Cl1-  [CuCl4]2- + 4H2O Green Blue • Increase Cl1- • Shift is forward • Products increase, reactants decrease • The Keq is the same – before and after Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  15. Complex Cu Ion System UP, UP AWAY [Cu(H2O)4 ] 2+ + 4Cl1-  [CuCl4]2- + 4H2O Green Blue • Increase H2O • Shift is reverse • Reactants increase, products decrease • The Keq is the same – before & after Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  16. Complex Co Ion System TAKE AWAY [CoCl4]2- + 6H2O  [Co(H2O)6]2+ + 4Cl- TOWARDS Pink Blue • Decrease H2O • Shift is reverse • Reactants increase, products decrease • The Keq is the same – before & after Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  17. Balanced Equation • 2NO2 (g)  N2O4 (g) + Energy • O2 (g) + 2SO2 (g) + Energy  2SO3 (g) • N2 (g)+ 3 H2 (g) 2NH3 (g)+ Energy • 2HI(g)+ Energy  H2 (g)+I2 (g) • O2 (g) + N2 (g) 2NO2 (g) • Keq = 4.5 x 10-31 at 25 ° C • Keq = 6.7 x 10-10 at 627 °C Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  18. Changes in Temperature 2NO2 (g)  N2O4 (g) + Energy • In a reversible reaction one direction is exothermic and the other direction is endothermic. • In the reaction above which direction is • exothermic? • forward • endothermic? • reverse Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  19. Changes in Temperature 2NO2 (g)  N2O4 (g) + Energy • Increasing the energy favors the endothermic reaction • Decreasing the energy favors the exothermic reaction • Keq is dependant on temperature • A change in temp, changes the Keq. Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  20. Equilibrium Constants Table Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  21. NO2 N2O4 System Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  22. NO2 N2O4 System AWAY 2NO2 (g)  N2O4 (g) + Energy UP, UP Brown Colorless • Increase Energy (temperature) • Shift is reverse • Products decrease, reactants increase • The Keq is decreasing Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  23. NO2 N2O4 System TOWARDS TAKE AWAY 2NO2 (g)  N2O4 (g) + Energy Brown Colorless • Decrease Energy (temperature) • Shift is forward • Products increase, reactants decrease • The Keq is increasing Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  24. Changes in Temperature Pb(s) + PbO(s) + 2H2SO4(aq)2PbSO4(s) + 2H2O(l) + E engine running storing energy that is taken in engine not running using energy that is given off Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  25. Balanced Equation • 2NO2 (g)  N2O4 (g) + Energy • O2 (g) + 2SO2 (g) + Energy  2SO3 (g) • N2 (g)+ 3 H2 (g) 2NH3 (g)+ Energy • 2HI(g)+ Energy  H2 (g)+I2 (g) • O2 (g) + N2 (g) 2NO2 (g) • Keq = 4.5 x 10-31 at 25 ° C • Keq = 6.7 x 10-10 at 627 °C Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  26. Effect of T, P & Conc Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  27. Chickens Lose Equilibrium CO2(g) CO2(aq) H2CO3(aq) H+ + HCO3- (aq)  H+ + CO3-2(aq) + Ca2+ CaCO3(s) EGGSHELL CHICKEN BREATH Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  28. Reactions that go to completion • If a product leaves the system the reaction will not reverse. It will go to completion. • Formation of a gas. • H2CO3 (aq) H2O(l) + CO2(g) • Formation of a precipitate. • Na+(aq)+Cl−(aq)+Ag+(aq)+NO3−(aq) Na+(aq)+NO3−(aq)+AgCl (s) Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  29. Common Ion Effect Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  30. Common Ion Effect UP, UP AWAY • The addition of HCl caused the NaCl to increase and precipitate out of solution. • Common-ion Effect - the addition of an ion common to two solutes brings about precipitation or reduced ionization. HCl (g) H+(aq) + Cl−(aq) NaCl (s) Na+(aq) + Cl−(aq) Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  31. Common Ion Effect NaC2H3O2  Na+ + C2H3O2- • Adding acetate ion from the dissociation of sodium acetate causes a reverse shift. • Ionization is reduced. [H3O+] is reduced. AWAY UP, UP HC2H3O2(aq)+ H2O(l)H3O+(aq)+ C2H3O2−(aq) Chapter 18 Section 2 Shifting Equilibrium p. 598-604

  32. Ch 18 Sec 2 Homework LeChatelier’s Principle Worksheet Chapter 18 Section 2 Shifting Equilibrium p. 598-604

More Related