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Chemical Equilibrium. Standard 9. Standard 9. Standard 9a – I will know how to use LeChatelier’s principle to predict the effect of changes in concentration, temperature , and pressure (volume).
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Chemical Equilibrium Standard 9
Standard 9 • Standard 9a – I will know how to use LeChatelier’sprinciple 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.
Standard 9a Symbols for Reversible Reactions Symbols for one way reactions
Compare and contrast rxn rates during Equilibrium Standard 9b • Only reversiblerxns can obtain equilibrium • Equilibrium: fwd rxnrate = reverse rxnrate
Are products and reactants equal in Equilibrium? Why? 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
Define LeChatelier’s Principle 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)
How does Concentration affect equilibrium? Standard 9a Concentration • If more [H2] is added….
Standard 9a Concentration …then reaction shifts to the ___ _ ? RIGHT
Standard 9a Concentration …then reaction shifts to the ___ _ ? RIGHT
Standard 9a Concentration If [H2] is removed….
Standard 9a Concentration …then reaction shift to the ___ _ ? LEFT
Standard 9a Concentration …then reaction shift to the ___ _ ? LEFT
How does Temperature affect equilibrium? Standard 9a Temperature Endothermic or Exothermic?
Standard 9a Temperature If Temperature is increased…..
Standard 9a Temperature Then the reaction will shift to the _____ ? LEFT
Standard 9a Temperature Then the reaction will shift to the _____ LEFT
Standard 9a Temperature If Temperature is decreased….. …………then the reaction will shift to the _____ RIGHT
Standard 9a Temperature Endothermic or Exothermic? Heat + H2O(s) H2O(l) If Temperature is increased….. …………then the reaction will shift to the _____ RIGHT
How does Pressure/Volume affect equilibrium? Standard 9a Pressure/Volume 3H2(g) + N2(g) 2NH3(g) + heat Incr. Pressure/Decr. Vol. shifts the equilibrium ______ ? RIGHT
Standard 9a Pressure/Volume 3H2(g) + N2(g) 2NH3(g) + heat Decr. Pressure/Incr. Vol. shifts the equilibrium ______ ? LEFT
Standard 9a • Decrease in Pressure/Increase of Volume shifts equilibrium which way???
Summary • What is equilibrium? • Are products and reactants equal at equilibrium? • How do the following change equilibrium: • Concentration? • Temperature? • Pressure?