1. Chemical Equilibrium Standard 9

2. Standard 9a – I will know how to use LeChatelier’s principle to predict the effect of changes in concentration, temperature, and pressure (volume). Standard 9b – I will know equilibrium is established when forward and reverse reaction rates are equal.

3. Standard 9a Symbols for Reversible Reactions  Symbols for one way reactions 

4. Standard 9b Only reversible rxns can obtain equilibrium Equilibrium: fwd rxn rate = reverse rxn rate Compare and contrast rxn rates during Equilibrium

5. Standard 9b Equilibrium: when there is no change in concentration of products or reactants Note: Concentration of reactants and products do not have to equal each other to be in equilibrium Are products and reactants equal in Equilibrium? Why?

6. Standard 9a LeChatelier's Principle: if a system at equilibrium is subjected to a stress, then the equilibrium will shift in a direction to relieve that stress. Stress: – Concentration – Temperature – Pressure (Volume) Define LeChatelier’s Principle

7. Standard 9a Concentration If more [H 2 ] is added…. How does Concentration affect equilibrium?

8. Standard 9a Concentration …then reaction shifts to the ___ _ ? RIGHT

9. Standard 9a Concentration …then reaction shifts to the ___ _ ? RIGHT

10. Standard 9a Concentration If [H 2 ] is removed….

11. Standard 9a Concentration …then reaction shift to the ___ _ ? LEFT

12. Standard 9a Concentration …then reaction shift to the ___ _ ? LEFT

13. Standard 9a Temperature Endothermic or Exothermic? How does Temperature affect equilibrium?

14. Standard 9a Temperature If Temperature is increased…..

15. Standard 9a Temperature Then the reaction will shift to the _____ ? LEFT

16. Standard 9a Temperature Then the reaction will shift to the _____ LEFT

17. Standard 9a Temperature If Temperature is decreased….. …………then the reaction will shift to the _____ RIGHT

18. Standard 9a Temperature Endothermic or Exothermic? Heat + H 2 O (s)  H 2 O (l) If Temperature is increased….. …………then the reaction will shift to the _____ RIGHT

19. Standard 9a Pressure/Volume 3H 2 (g) + N 2 (g)  2NH 3 (g) + heat Incr. Pressure/Decr. Vol. shifts the equilibrium ______ ? RIGHT How does Pressure/Volume affect equilibrium?

20. Standard 9a Pressure/Volume 3H 2 (g) + N 2 (g)  2NH 3 (g) + heat Decr. Pressure/Incr. Vol. shifts the equilibrium ______ ? LEFT

21. Standard 9a Decrease in Pressure/Increase of Volume shifts equilibrium which way???

22. Summary What is equilibrium? Are products and reactants equal at equilibrium? How do the following change equilibrium: – Concentration? – Temperature? – Pressure?