1. AP Chemistry Chapter 15 Jeopardy Jennie L. Borders

2. Round 1 – Chapter 15

3. KQ Calculating Equilibrium Constants Applications of k Le Chatelier’s Principle Surprise 100 200 300 400 500

4. k 100 k 100 Write the equilibrium constant expression for the following reaction: 2C 2 H 4(g) + 2H 2 O (g)  2C 2 H 6(g) + O 2(g) K c = [C 2 H 6 ] 2 [O 2 ] K c = [C 2 H 6 ] 2 [O 2 ] [C 2 H 4 ] 2 [H 2 O] 2 [C 2 H 4 ] 2 [H 2 O] 2

5. k 200 Write the equilibrium constant expression for the following reaction: 4HCl (aq) + O 2(g)  2H 2 O (l) + 2Cl 2(g) K c = [Cl 2 ] 2 _ [HCl] 4 [O 2 ] [HCl] 4 [O 2 ]

6. k 300 Does the following reaction favor the production or reactants or products? 2HBr (g)  H 2(g) + Br 2(g) K c = 5.8 x 10 -18 reactants

7. k 400 Calculate K c at 303K for SO 2(g) + Cl 2(g)  SO 2 Cl 2(g) if K p = 34.5 at the temperature. 858.23

8. k 500 Consider the equilibrium N 2 + O 2 + Br 2  2NOBr Calculate the equilibrium constant K p for this reaction, given the following information at 298K: 2NO + Br 2  2NOBr K c = 2.0 2NO  N 2 + O 2 K c = 2.1 x 10 30 K p = 3.89 x 10 -32

9. Q 100 If Q c > K c, how must the reaction proceed to reach equilibrium? left

10. Q 200 What is the difference between Q and K? K uses equilibrium concentrations or partial pressures and Q uses concentrations or partial pressures at any time.

11. Q 300 K p for the equilibrium N 2(g) + 3H 2(g)  2NH 3(g) is 4.51 x 10 -5 at 450 o C. Indicate whether the mixture is at equilibrium. If it is not at equilibrium, indicate the direction in which the reaction must shift to achieve equilibrium. 98 atm NH 3, 45 atm N 2, 55 atm H 2 1.28 x 10 -3 shifts to the left

12. Q 400 K p for the equilibrium N 2(g) + 3H 2(g)  2NH 3(g) is 4.51 x 10 -5 at 450 o C. Indicate whether the mixture is at equilibrium. If it is not at equilibrium, indicate the direction in which the reaction must shift to achieve equilibrium. 57 atm NH 3, 143 atm N 2, and no H 2 0 in denominator, shifts to the left

13. Q 500 K p for the equilibrium N 2(g) + 3H 2(g)  2NH 3(g) is 4.51 x 10 -5 at 450 o C. Indicate whether the mixture is at equilibrium. If it is not at equilibrium, indicate the direction in which the reaction must shift to achieve equilibrium. 13 atm NH 3, 27 atm N 2, and 82 atm H 2 1.14 x 10 -5 shifts to the right

14. Calculating Equilibrium Constants 100 An equilibrium mixture in a 2L vessel is found to contain 0.0406 mol CH 3 OH, 0.170 mol CO, and 0.302 mol H 2 at 500K. Calculate K c at this temperature. CO (g) + 2H 2(g)  CH 3 OH (g) 10.47

15. Calculating Equilibrium Constants 200 The equilibrium NO (g) + Cl 2(g)  NoCl (g) is established at 500K. An equilibrium mixture of the three gases has partial pressures of 0.095 atm NO, 0.171 atm Cl 2, and 0.28 atm NOCl. Calculate K p for this reaction 50.8

16. Calculating Equilibrium Constants 300 A flask contains 1.5 atm N 2 O 4 and 1 atm NO 2 and the following equilibrium is achieved N 2 O 4(g)  2NO 2(g). After equilibrium is reached, the partial pressure of NO 2 is 0.512 atm. Calculate the value of K p for this reaction. 0.1503

17. Calculating Equilibrium Constants 400 A mixture of 0.2 mol CO 2, 0.1 mol H 2, and 0.16 mol H 2 O is placed in a 2L vessel. The following equilibrium is established: CO 2(g) + H 2(g)  CO (g) + H 2 O (g). At equilibrium P H2O = 3.51 atm. Calculate K p for the reaction at 500K. 0.11

18. Calculating Equilibrium Constants 500 A mixture of 1.374g H 2 and 70.31g Br 2 is heated in a 2L vessel at 700K. These substances react as follows: H 2(g) + Br 2(g)  2HBr (g). At equilibrium the vessel is found to contain 0.566g of H 2. Calculate K c. (keep 4 decimal places) 67.61

19. Applications of k 100 At 100 o C, K c = 0.078 for the reaction SO 2 Cl 2(g)  SO 2(g) + Cl 2(g). In an equilibrium mixture of the three gases, the concentrations of SO 2 Cl 2 is 0.180M and SO 2 is 0.052M. What is the concentration of Cl 2 in the equilibrium mixture? 0.162M

20. Applications of k 200 At 900K the following reaction has K p = 0.345: 2SO 2(g) + O 2(g)  2SO 3(g). In an equilibrium mixture the partial pressures of SO 2 is 0.135 atm and O 2 is 0.455 atm. What is the equilibrium partial pressure of SO 3 in the mixture? 0.054 atm

21. Applications of k 300 At 373K, K p = 0.416 for the equilibrium 2NOBr (g)  2NO (g) + Br 2(g). If the pressures of NOBr (g) and NO (g) are equal, what is the equilibrium pressure of Br 2(g) ? 0.416 atm

22. Applications of k 400 At 218 o C, K c = 1.2 x 10 -4 for the equilibrium NH 4 HS (s)  NH 3(g) + H 2 S (g). Calculate the equilibrium concentrations of NH 3 and H 2 S if a sample of solid NH 4 HS is placed in a closed vessel and decomposes until equilibrium is reached. [NH 3 ] = 0.011M, [H 2 S] = 0.011M

23. Applications of k 500 For the equilibrium Br 2 + Cl 2  2BrCl at 400K, K c = 7.0. If 0.2 mol Br 2 and 0.25 mol Cl 2 are introduced into a 1L container at 400K, what will be the equilibrium concentrations of Br 2, Cl 2, and BrCl? [Br 2 ] = 0.073 M, [Cl 2 ] = 0.123 M, [BrCl] = 0.254 M

24. Le Chatelier’s Principle 100 Consider 4NH 3(g) + O 2(g)  4NO (g) +6H 2 O (g),  H = -904.4kJ. How does increasing [NH 3 ] affect the yield of NO at equilibrium? Equilibrium shifts to the right, so [NO] increases.

25. Le Chatelier’s Principle 200 Consider 4NH 3(g) + O 2(g)  4NO (g) +6H 2 O (g),  H = -904.4kJ. How does decreasing [O 2 ] affect the yield of NO at equilibrium? Consider 4NH 3(g) + O 2(g)  4NO (g) +6H 2 O (g),  H = -904.4kJ. How does decreasing [O 2 ] affect the yield of NO at equilibrium? Equilibrium shifts to the left, so [NO] decreases.

26. Le Chatelier’s Principle 300 Consider 4NH 3(g) + O 2(g)  4NO (g) +6H 2 O (g),  H = -904.4kJ. How does decreasing the volume of the container in which the reaction occurs affect the yield of NO at equilibrium? Equilibrium shifts to the left, so [NO] decreses.

27. Le Chatelier’s Principle 400 Consider 4NH 3(g) + O 2(g)  4NO (g) +6H 2 O (g),  H = -904.4kJ. How does adding a catalyst affect the yield of NO at equilibrium? No shift in equilibrium, so no change in [NO].

28. Le Chatelier’s Principle 500 Consider 4NH 3(g) + O 2(g)  4NO (g) +6H 2 O (g),  H = -904.4kJ. How does increasing temperature affect the yield of NO at equilibrium? Equilibrium shifts to the left, so [NO] decreases.

29. Surprise 100 At 1000K, K p = 1.85 for the reaction SO 2(g) + 1/2O 2(g)  SO 3(g). What is the value of K p for the reaction SO 3(g)  SO 2(g) + 1/2O 2(g) ? 0.541

30. Surprise 200 Consider the following equilibrium: 2H 2(g) + S 2(g)  2H 2 S (g) K c = 1.08 x 10 7 at 700 o C. Does the equilibrium mixture contain mostly H 2 and S 2 or mostly H 2 S? H2SH2SH2SH2S

31. Surprise 300 When 2.00 mol of SO 2 Cl 2 is placed in a 2L flask at 303K, 56% of the SO 2 Cl 2 decomposes to SO 2 and Cl 2 : SO 2 Cl 2(g)  SO 2(g) + Cl 2(g). Calculate K c for this reaction at this temperature. 0.713

32. Surprise 400 A mixture of CH 4 and H 2 O is passed over a nickel catalyst at 1000K. The emerging gas is collected in a 5L falsk and is found to contain 8.62g CO, 2.6g H 2, 43g CH 4, and 48.4g H 2 O. Assuming that equilibrium has been reached, calculate K c for the reaction. 3.74 x 10 -3

33. Surprise 500 At 80 o C, K c = 1.87 x 10 -3 for the reaction PH 3 BCl 3(s)  PH 3(g) + BCl 3(g). Calculate the equilibrium concentrations of PH 3 and BCl 3 if a solid sample of PH 3 BCl 3 is placed in a closed vessel and decomposes until equilibrium is reached. [PH 3 ] = 0.043M, [BCl 3 ] = 0.043M