3. Ch 18 Reaction Rates You have 5 minutes You have 5 minutes Vocab out½ sheet of paper Vocab out½ sheet of paper A tablet will be dropped into hot water and cold water. A tablet will be dropped into hot water and cold water. A powdered tablet will be dropped into hot water and cold water. A powdered tablet will be dropped into hot water and cold water. Rank the reactions in terms of speed of completion (1-4), which will be first and last to complete. Explain, 3-4 sentences. Rank the reactions in terms of speed of completion (1-4), which will be first and last to complete. Explain, 3-4 sentences.

4. 10% per round reversible reaction At the start of each round 10% of A pennies are passed to B while 10% of B pennies are passed to A. (DO NOT PASS THEN COUNT 10%, count your pennies at the start of each round and then pass them to the other pile, round to whole numbers) At the start of each round 10% of A pennies are passed to B while 10% of B pennies are passed to A. (DO NOT PASS THEN COUNT 10%, count your pennies at the start of each round and then pass them to the other pile, round to whole numbers) A starts with 100 A starts with 100 B starts with 0 B starts with 0 Create a table and graph that shows the pennies at the start of each round. Create a table and graph that shows the pennies at the start of each round. Do 15 rounds Do 15 rounds You have 5 minutes You have 5 minutes

5. 10% / 20% reversible reaction At the start of each round 10% of A pennies are passed to B while 20% of B pennies are passed to A. (DO NOT PASS THEN COUNT 10%, count your pennies at the start of each round, round to whole numbers) At the start of each round 10% of A pennies are passed to B while 20% of B pennies are passed to A. (DO NOT PASS THEN COUNT 10%, count your pennies at the start of each round, round to whole numbers) A starts with 100 A starts with 100 B starts with 0 B starts with 0 Create a table and graph that shows the pennies at the start of each round. Create a table and graph that shows the pennies at the start of each round. Do 15 rounds, you have 5 minutes Do 15 rounds, you have 5 minutes

6. Reaction Rates and equilibrium Reaction Rates and equilibrium

7. Rate = time interval that a change occurs in (s, min, day…) amount of reactant changing per unit time. Example g/hr, mol/s

8. Collision theory – when atoms, ions, molecules collide they can form a bond if the KE is high enough (and orientation is right) How can you increase KE?

9. activation energy= minimum energy colliding particles must have in order to react

11. Factors affecting reaction rates

12. Temperature - more collisions more energetic (higher KE)

13. Does milk spoil in your refrigerator?

14. Concentration – more particles usually more collisions

15. Particle size – usually more surface area equals more collisions (smaller particles react faster)

16. Catalyst- lowers the activation energy(more collisions are effective) but does not react itself

17. Section 18.2 Reversible reactions – react in both directions simultaneously

18. Chemical equilibrium – forward and reverse reactions take place at the same time

19. Is the water in this bottle evaporating?

21. Factors that affect equilibrium

22. Concentration, pressure, temperature will cause a shift in equilibrium ex. More products formed

23. Le Châtelier’s principle: a stress is applied to a system in dynamic equilibrium, the system changes to relieve the stress. Ex. More products formed

24. Predict the change in equilibrium 1. Remove O 2 2. Add O 2 3. increase pressure 4. decrease pressure

25. Predict the change in equilibrium 1. heat mixture 2. add SO 2 3. remove SO 3 4. cool mixture

26. Equilibrium constant Are products or reactants favored? Concentration [molarity…] raised to the coefficient -products over reactants-

27. Keq >1 products are favored Keq 1 products are favored Keq < 1 reactants are favored

28. N 2(g) + 3H 2(g)  2NH 3(g) At equilibrium, a 5-L flask contains 0.30 mol N 2, 0.50 mol H 2, and 0.20 mol NH 3. Calculate K eq for the reaction.

29. Calculate molarity then use the the equation to calculate K eq.

30. N 2(g) + 3H 2(g)  2NH 3(g) produces ammonia, which is a fertilizer. At equilibrium, a 5-L flask contains 0.30 mol N 2, 0.50 mol H 2, and 0.20 mol NH 3.

38. End day one notes

39. 1) Calculate the equilibrium constant when 0.275 mol of SO 2 and 0.125 mol of O 2 are in a 1.25L container with 0.511 mol of SO 3. 1) Calculate the equilibrium constant when 0.275 mol of SO 2 and 0.125 mol of O 2 are in a 1.25L container with 0.511 mol of SO 3. 2a) Which way will the equilibrium shift if some O 2 is removed? 2a) Which way will the equilibrium shift if some O 2 is removed? 2b) Which way will the equilibrium shift if the pressure is increased? 2b) Which way will the equilibrium shift if the pressure is increased?

40. Work/Answers 1) 0.4088^2 / (.22^2 x 0.1) 1) 0.4088^2 / (.22^2 x 0.1) 0.16711744 /.00484 = keq = 34.5 0.16711744 /.00484 = keq = 34.5 Left, to replenish O 2 Left, to replenish O 2 Right, less gas moles Right, less gas moles

41. Calculate the equilibrium constant when 0.275 mol of SO 2 and 0.125 mol of O 2 are in a 1.00L container with 0.511 mol of SO 3. Calculate the equilibrium constant when 0.275 mol of SO 2 and 0.125 mol of O 2 are in a 1.00L container with 0.511 mol of SO 3. If the pressure is increase what amounts in the previous problem would change?

42. 1) Calculate the equilibrium constant when 0.475 mol of SO 2 and 0.225 mol of O 2 are in a 1.25L container with 0.611 mol of SO 3. 1) Calculate the equilibrium constant when 0.475 mol of SO 2 and 0.225 mol of O 2 are in a 1.25L container with 0.611 mol of SO 3. 2a) Which way will the equilibrium shift if some O 2 is removed? 2a) Which way will the equilibrium shift if some O 2 is removed? 2b) Which way will the equilibrium shift if the pressure is increased? 2b) Which way will the equilibrium shift if the pressure is increased? Quiz

43. 1) Calculate the equilibrium constant when 0.475 mol of SO 2 and 0.225 mol of O 2 are in a 1.25L container with 0.611 mol of SO 3. 1) Calculate the equilibrium constant when 0.475 mol of SO 2 and 0.225 mol of O 2 are in a 1.25L container with 0.611 mol of SO 3. 2a) Which way will the equilibrium shift if some O 2 is removed? Left, to replenish the supply of oxygen 2a) Which way will the equilibrium shift if some O 2 is removed? Left, to replenish the supply of oxygen 2b) Which way will the equilibrium shift if the pressure is increased? Right, the 2 moles occupy less space and is more favorable 2b) Which way will the equilibrium shift if the pressure is increased? Right, the 2 moles occupy less space and is more favorable Quiz answers

44. 18.3 solubility equilibrium=K sp equilibrium of insoluble salts DROP THE SOLID

45. The smaller the K sp, the lower the solubility of the compound.

46. What is the concentration of Calcium ions in a saturated CaSO 4 solution at 100  C? (K sp = 4.5 x10 -9 )

47. CaSO 4 (s)  Ca 2+ (aq) + SO 4 2- (aq)

48. common ion = is found in both salts in a solution How would adding NaCl (aq) shift this reaction? common ion = is found in both salts in a solution How would adding NaCl (aq) shift this reaction?

49. common ion effect = lowering of the solubility of an ionic compound as a result of the addition of a common ion

50. What is the concentration of sulfide ions in a 1.0-L solution of FeS to which 0.04 mol of iron (II) chloride is added? The Ksp of FeS is 8 x 10 -19

52. 18.4 entropy and free energy

53. Free energy is the released energy able to do work

54. some of the energy liberated in chemical reaction can be harnessed to do work, such as driving the pistons of an internal-combustion engine.

55. The internal-combustion engine in a car is only about 30% efficient; that is, only about 30% of the free energy released by burning gasoline is used to propel the car.

57. Spontaneous reactions = substantial amounts of products at equilibrium and release free energy

58. nonspontaneous reaction = does not favor the formation of products at the specified conditions

59. Some reactions that are spontaneous at one set of conditions may not be at another

60. law of disorder = the natural tendency is for systems to move in the direction of maximum disorder

61. What are the odds that a tornado hit this room?

63. An increase in entropy (more random) favors the spontaneous chemical reaction; as does a decrease in enthalpy (exothermic)

64. The size and direction of enthalpy changes and entropy changes together determine whether a reaction is spontaneous

78. Spontaneous reactions naturally favor the formation of products

79. Law of disorder – Things move in the direction of maximum entropy (disorder)