1. What is ? Effective collision? Collision theory? Factors affecting? Activation energy? Energy level diagram? Rate of reaction

2. What is the rate of a reaction The rate of the reaction is how quickly the reaction happens. Fast reaction Slow reaction

3. Iron rusting - a CHEMICAL REACTION with a slow reaction rate. Wood burning - a CHEMICAL REACTION with a fast reaction rate .

4. What is ? Effective collision? Collision theory? Factors affecting? Activation energy? Energy level diagram? Rate of reaction

5. "You can’t react if you don’t collide." collision theory

10. What is ? Effective collision? Collision theory? Factors affecting? Activation energy? Energy level diagram? Rate of reaction

11. Prevent Effective collision Camera to detect fast moving traffic

12. Reactants moving too slowly Molecules bounce ( no reaction) NO 3(gas) + CO (gas)  NO 2(gas) + CO 2(gas) NOT Effective collision

13. NO 3(gas) + CO (gas)  NO 2(gas) + CO 2(gas) Reactants not facing right way Molecules bounce ( no reaction) NOT Effective collision

14. Reactants energy is high & oriented right way Reaction happens Effective collision

15. The orientation of collision Effective collision

16. Effective collision

17. Effective collision Which collision is effective?

18. What is ? Effective collision? Collision theory? Factors affecting? Activation energy? Energy level diagram? Rate of reaction

20. The sparks generated by striking steel against a flint provide the activation energy to initiate combustion in this Bunsen burner Activation energy

21. A little activation energy is added with the aid of a weed burner... What is activation energy

22. Not enough kinetic energy for reactants to leap over reaction barrier. A "hot" reaction in progress showing reactants leaping over the activation energy barrier What is activation energy

23. Activation energy

24. Activation energy

25. Only collisions with enough energy react to form products. The critical amount of energy to make the reaction proceed What is activation energy

26. A + B  C + D reactants products

27. What is activation energy activation energy

28. What is activation energy reactants products Activation energy

29. What is activation energy reactants products Activation energy

30. What is activation energy reactants products

31. What is ? Effective collision? Collision theory? Factors affecting? Activation energy? Energy level diagram? Rate of reaction

32. What affects the rate of a reaction? Size of reactant Concentration of reactants /pressure Temperature of reaction mixture catalyst

33. 1. The effect of particle size What affects the rate of a reaction?

34. 1. The effect of particle size

36. Increasing the Surface Area of a Solid. A solid in a solution can only react when particles collide with the surface. The bigger the area of the solid surface, the more particles can collide with it per second A powder has the largest surface area and will have the fastest reaction rate.

37. THE EFFECT OF SURFACE AREA ON REACTION RATES a reaction between magnesium metal and a dilute acid like hydrochloric acid. Increasing the number of collisions per second increases the rate of reaction.

38. THE EFFECT OF SURFACE AREA ON REACTION RATES Magnesium metal

39. THE EFFECT OF SURFACE AREA ON REACTION RATES Magnesium metal

40. What affects the rate of a reaction? 2. Temperature Increasing temperature will increase energy in the particles leads to an increased probability of favourable collisions .

42. 3. Concentration and Pressure Increasing concentration or pressure increases the rate of a reaction, because the particles are closer together and have an increased probability of favourable collisions. What affects the rate of a reaction?

44. THE EFFECT OF CONCENTRATION ON REACTION RATES

45. THE EFFECT OF CONCENTRATION ON REACTION RATES

47. THE EFFECT OF PRESSURE ON REACTION RATES

48. THE EFFECT OF PRESSURE ON REACTION RATES

50. 4. Catalyst Often a catalyst is there to provide a favourable surface for a reaction to take place What affects the rate of a reaction? The black object represents the catalyst

52. Examples CATALYSTS ON REACTION RATES Reaction catalyst Decomposition of hydrogen peroxide Manganese (IV) oxide, MnO 2 Manufacture of ammonia by the Haber Process Iron Contact Process to make sulphuric acid Vanadium (V) oxide, V 2 O 5

54. 4. Catalyst How does a catalyst work? 1) A catalyst provides a surface on which the reaction can take place. This increases the number of collisions between the particles of the substances that are reacting. What affects the rate of a reaction?

55. How does a catalyst work?

56. How does a catalyst work?

57. 4. Catalyst How does a catalyst work? 2) A catalyst lowers the activation energy This means that the particles can react with less energy than they needed before the catalyst was added. (Think about it: if the government lowered the legal age to buy cigarettes , then more people could legally buy cigarettes. Similarly, if we lower the amount of energy needed for particles to react, then more particles can react ). What affects the rate of a reaction?

58. A catalyst provides an alternative route for the reaction. That alternative route has a lower activation energy. Activation energy

59. Activation energy Activation energy with no catalyst Activation energy with catalyst

60. What is ? Effective collision? Collision theory? Factors affecting? Activation energy? Energy level diagram? Rate of reaction

61. In an exothermic reaction, reactants have a higher energy level than the products. Energy level diagram

62. In endothermic reactions the reactants have a lower energy level than the products. Energy level diagram

63. End of slides