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Equilibrium

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Equilibrium

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    1. Equilibrium

    2. Equilibrium Limiting reagent Concentrations become constant Dynamic situation Reversible reactions Equilibrium reactions are reversible reactions: ? Equilibrium reactions are reversible reactions: ?

    3. 2NO2 ? N2O4

    4. 2NO2 ? N2O4 NO2 is a dark brown gas N2O4 is light brownNO2 is a dark brown gas N2O4 is light brown

    5. Equilibrium Constant (K) Upper case = reactants and products Lower case letters are number of molesUpper case = reactants and products Lower case letters are number of moles

    6. Equilibrium Constant (K) Brackets mean moles/liter or Molarity [C]c equals the concentration of reactant C raised to c powerBrackets mean moles/liter or Molarity [C]c equals the concentration of reactant C raised to c power

    7. Equilibrium Constant (K) [ ] represents concentration in mol/L for (g) and (aq), only Each [ ] must be raised to the power of its coefficient

    8. Equilibrium Constant (K) K < 1 indicates little product formation K > 100 indicates great amount of product formation

    9. Equilibrium Constant (K) Write the K expression for the dimerization of nitrogen dioxide.

    10. Equilibrium Constant (K) [N2O4] [NO2]2 What will the units of K be in this example?

    11. Equilibrium Constant (K) At 25C, the equilibrium concentrations of NO2 and N2O4 are 0.0370M and 0.2315M. What is the value of K at this T?

    12. Equilibrium Constant (K) [0.2315] [0.037]2

    13. N2 + 3H2 ? 2NH3 Write the K expression for the synthesis of ammonia.

    14. Equilibrium Constant (K) [NH3]2 [N2][H2]3 What will the units of K be in this example?

    15. Equilibrium Constant (K) At 300C, the equilibrium concentrations are: [N2]eq= 2.59M [H2]eq=2.77M [NH3]eq=1.82M What is the value of K at this temperature?

    16. Equilibrium Constant (K) [1.82]2 [2.59][2.77]3

    17. Equilibrium Constant (K) Small K (<1) means Big K (>100) means Different manner of solving problems Small K (<1) a lot of reactant Big K (>100) a lot of productSmall K (<1) a lot of reactant Big K (>100) a lot of product

    18. Equilibrium Constant (K) If a reaction is reversed, then the value of K for the reversed reaction is the reciprocal of K.

    19. Equilibrium Constant (K) So, if the dimerization of NO2 is reversed to be the decomposition of N2O4

    20. Equilibrium Constant (K) K = (169 L/mol)-1 or 0.00592 mol/L

    21. Equilibrium Constant (K) At 25C, the initial concentration of N2O4 is 0.750M. What are the eq. conc. of both species at this temperature?

    22. Equilibrium Constant (K) You will make an equilibrium chart to indicate the initial, change, and equilibrium concentrations.

    23. Equilibrium Constant (K) Change line reflects the mole to mole ratioChange line reflects the mole to mole ratio

    24. Equilibrium Constant (K)

    25. Equilibrium Constant (K)

    26. Equilibrium Constant (K) [2x]2 [0.75 x]

    27. Equilibrium Constant (K)

    28. Equilibrium Constant (K)

    29. Equilibrium Constant (K)

    30. Equilibrium Constant (K)

    31. Equilibrium Constant (K)

    32. Equilibrium Constant (K) [0.0666]2 [0.7167]

    33. Equilibrium Constant (K) At 25C, the initial concentration of NO2 is 0.500M. What are the eq. conc. Of both species at this temperature? Remember that K = 169L/mol.

    34. Equilibrium Constant (K) Since K is big, lots of product will be made. Thus, almost all of the initial amount of reactant will be used. You need to make two charts for a big K problemStoichiometry and Equilibrium

    35. Equilibrium Constant (K) Stoichiometry Chart

    36. Equilibrium Constant (K) Stoichiometry Chart

    37. Equilibrium Constant (K) Stoichiometry Chart

    38. Equilibrium Constant (K) Equilibrium Chart

    39. Equilibrium Constant (K) Equilibrium Chart

    40. Equilibrium Constant (K) Equilibrium Chart

    41. Equilibrium Constant (K) [0.25 - x] [2 x]2

    42. Equilibrium Constant (K)

    43. Equilibrium Constant (K)

    44. Equilibrium Constant (K) Since the assumption that x was so small it was negligible is bad, then you must re-insert x and solve the equation with x present.

    45. Equilibrium Constant (K) [0.25 - x] [2 x]2

    46. Equilibrium Constant (K)

    47. Equilibrium Constant (K) You will get two values of x. If both are positive, then you will always select the smaller one. If one is positive and the other negative, you will select the positive one.

    48. Equilibrium Constant (K)

    49. Equilibrium Constant (K)

    50. Equilibrium Constant (K)

    51. Equilibrium Constant (K) Equilibrium Chart

    52. Equilibrium Constant (K) [0.2315] [0.037]2

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