1. Equilibrium Jeopardy ConceptsEquilibrium expression Finding KeqFinding QLe Chatelier’s 10 20 30 40 50

2. What happens to the concentrations of reactants and products at equilibrium? Category 1 – 10 points

3. Stays constant/stable Category 1 – 10 points

4. What happens to the forward and reverse rates of reactions at equilibrium? Category 1 – 20 points

5. They are the same/equal Category 1 – 20 points

6. In the graph above, what substance(s) are present initially? Category 1 – 30 points

7. X

8. Using a colorimeter you test the absorbance of [FeSCN +2 ] eq. It is 0.562. A “standard” of the reaction is measured, which has a concentration of 0.04M and absorbance of 0.824. What is [FeSCN +2 ] eq ? Category 1 – 40 points

9. .027M Category 1 – 40 points

10. At what time has equilibrium been reached in the graph above Category 1 – 50 points

11. 7 min Category 1 – 50 points

12. Write the equilibrium expression for the following reaction C 3 H 8(g) + 5O 2(g) ↔ 3CO 2(g) + 4H 2 O (g) Category 2 – 10 points

13. [H 2 O] 4 [CO 2 ] 3 [C 3 H 8 ] [O 2 ] 5 Category 2 – 10 points

14. Write the equilibrium expression for the following reaction S(s) + O 2 (g) ↔ SO 2 (g) Category 2 – 20 points

15. [ SO 2 ] [O 2 ] Category 2 – 20 points

16. Write the equilibrium expression for the following equation Heat + C (s) + CO 2(g) ↔ 2CO (g) Category 2 – 30 points

17. [CO] 2 [CO 2 ] Category 2 – 30 points

18. Consider the equation Fe +3 (aq) + SCN - (aq)  FeSCN +2 (aq) If you have initial concentrations of [Fe] =.42 and [SCN] =.87 and you find the equilibrium concentration of [FeSCN] to be.22. Find Keq. Category 2 – 40 points

19. 1.69 Category 2 – 40 points

20. Consider the following reaction: Fe +3 (aq) + SCN - (aq)  FeSCN +2 (aq) The reaction starts with 2 mL of 0.4M Fe(NO 3 ) 3 and 8 mL of 0.2 M KSCN. After being mixed in a test tube, you need to calculate initial concentrations of Fe +3 and SCN -1. What is the [SCN -1 ] i ? Category 2 – 50 points

21. .16M Category 2 – 50 points

22. Physical Challenge!!!! Category 3 – 10 points

24. For the reaction 2NO(g) + O2(g) ↔ 2NO2(g) the equilibrium concentrations were found to be [NO2] = 3.0 x 10 -2 M, [O2] = 1.0 x 10 -2 M, and [NO] = 6.0 x 10 -3 M. Calculate the value of the equilibrium constant from these data. Category 3 – 20 points

25. 2500 Category 3 – 20 points

26. CO(g) + H2O(g) ↔ CO2(g) + H2(g) and K eq = 4.88 at a certain temperature. If at this temperature in a certain experiment [H2] = 1.4 M, [CO2] = 1.8 M, and [H2O] =.26 M, calculate [CO]. Category 3 – 30 points

27. 1.986M Category 3 – 30 points

28. What can be said about amounts of reactants and products if a reaction has a very small Keq (less than 1) Category 3 – 40 points

29. There are more reactants than products Category 3 – 40 points

30. Given the reaction A(g) + B(g) ↔ C(g) + D(g). You have the gases A, B, C, and D at equilibrium. What happens to the value of K eq when gas B is added? Category 3 – 50 points

31. Nothing, Keq does not change due to change in concentrations Category 3 – 50 points

32. Physical Challenge!!!!! Category 4 – 10 points

33. What is always true of the relationship of Q and Keq at equilibrium Category 4 – 20 points

34. They are equal Category 4 – 20 points

35. Keq for the reaction 2NO 2(g)  N 2 O 4(g) is 2.73. If a container holds 4.10 M N 2 O 4 and 8.87X 10 -2 M NO 2, what is the value of Q? In what direction will the reaction proceed? Category 4 – 30 points

36. 521 to the left Category 4 – 30 points

37. Physical Challenge!!!! Category 4 – 40 points

39. If the value of Q were computed at time = 2 minutes, how would it compare to the value of K eq in the figure above Category 4 – 50 points

40. Q<keq Category 4 – 50 points

41. Is this an exothermic or endothermic reaction? Category 5 – 10 points

42. Exothermic Category 5 – 10 points

43. Which type of stress causes Keq to change? Category 5 – 20 points

44. Temperature change Category 5 – 20 points

45. What does Le Chatelier’s principle help us to do? Category 5 – 30 points

46. Determine how reaction positions will react in response to stress Category 5 – 30 points

47. Consider the following reaction: Fe +3 (aq) + NO 3 -1 (aq) + K +1 (aq) + SCN -1 (aq)  FeSCN +2 (aq) + K +1 + NO 3 -1 The reactants are clear and the products are red. Once this reaction reaches equilibrium, an aqueous solution of Fe(NO 3 ) 3 is added to the reaction. What will happen to the concentration of SCN? Category 5 – 40 points

48. It will decrease Category 5 – 40 points

49. A reaction is exothermic. Once it reaches equilibrium you add heat to the system. What happened to the value of Keq once you add the heat? Category 5 – 50 points

50. Keq gets smaller Category 5 – 50 points