1. CHAPTER 1 RATE OF REACTION

2. 1.1 RATE OF REACTION Why a tall building can be destroyed with explosives within seconds??

3. Why food has to take several hours to be decay ??

4. Why do coal mines face a high risk of explosion ??

5. All these are because : difference of rate of reaction

8. 1. Fireworks display occurs in just a few seconds Rate of reaction HIGH

9. 2. The photosynthesis process takes a few hours Rate of reaction LOWER

10. 3. The erosion process of stones takes many years Rate of reaction VERY LOW

11. Some reactions are fast & some reactions are very slow So do the chemical reactions in laboratory

12. How we determine & calculate the rate of chemical reactions in laboratory ??

13. It just same with the way we calculate the speed of driving How we calculate the speed of driving ??

14. Yes, the formulae is : Speed = distance (km) time (hour)

15. In the other hand, it is : Rate of = physical changes reaction time

19. Decomposition of hydrogen peroxide to form water and oxygen gas H 2 O 2 (aq) H 2 O (l) + O 2 (g)

20. Take 5

21. For any chemical reaction, we can measure its average rate of reaction & rate of reaction at a given time

22. What’s that ??

23. Rate of = physical changes reaction time average rate of reaction rate of reaction at a given time Average rate = total changes of reaction total time taken Rate of reaction at a given time = gradient of the curve at that instant = y 2 – y 1 / X 2 – X 1

24. Total changes Total time taken Average rate = total changes of reaction total time taken Volume of hydrogen gas ( cm 3 ) Time ( s )

27. Let’s see an example:

28. CaCO 3 + HCl  CaCl 2 + H 2 O + H 2 burette water Hydrochloric acid Marble chips Hydrogen gas

29. Volume of hydrogen gas was recorded every 30 seconds

30. . . . . . . . . . . . . . . . . after 10 minutes . . .

31. Here’s the result : Time / s Reading of burette / cm 3 Volume of gas / cm 3

32. Then we plot the graph: Volume of hydrogen gas ( cm 3 ) Time ( s ) 5 10 0 35 30 25 20 15 60 30 90 180 210 240 270 300 150 120

34. Average rate of reaction = total changes / total time taken Average rate of reaction = 34 cm 3 300 s = 0.113 cm 3 s -1 ** you’ll get the same answer by using graph

36. b) Calculate the average rate of reaction in the first 90 seconds . Solution: this is accumulated !! Time / s Reading of burette / cm 3 Volume of gas / cm 3

37. Average rate of reaction = total changes / total time taken Average rate of reaction = 20 cm 3 90 s = 0.222 cm 3 s -1 ** you’ll get the same answer by using graph

40. Solution (a) : 22.00 – 10.50 = 11.50 cm 3 90-30 = 60 s Rate of reaction at 60 second = y 2 – y 1 x 2 - x 1 = 22.00 -10.50 90 -30 = 11.50 cm 3 60 s = 0.192 cm 3 s -1 ** 5 10 35 30 25 20 15 Time ( s ) 90 Volume of hydrogen gas ( cm 3 ) 0 60 30 180 210 240 270 300 150 120

41. Solution (b) : 35.50 – 30.00 = 5.50 cm 3 255-160 = 95 s Rate of reaction at 210 second = 35.50 -30.00 255 -160 = 5.50 cm 3 95 s = 0.058 cm 3 s -1 ** 5 10 35 30 25 20 15 Time ( s ) 90 Volume of hydrogen gas ( cm 3 ) 0 60 30 180 210 240 270 300 150 120

47. Conclusion Rate of reaction very high Rate of reaction lower Curve becomes horizontal line No more reaction occur Rate of reaction = 0 cm 3 s -1 Rate of reaction More lower Total volume of gas Liberated (cm 3 ) Time (s / min)

48. Learning Task 1.2 page 8 WORKSHOP HOUR

50. 1.2 Factors affecting the rate of reaction

51. Some reactions are fast & some reactions are very slow So do the chemical reactions in laboratory

52. What are the factors affect the rate of reaction ??

53. 2. T emperature 1. T otal surface area 4. C atalyst 5. P ressure 3. C oncentration 2T 2C 1P

54. How does the factors of Total surface area, Temperature, Concentration, Catalyst & Pressure affect the reaction rate?? 2T 2C 1P

55. Let’s do the experiment to investigate that: 1.Surface area smaller , rate of reaction 2.Concentration higher, rate of reaction 3.Temperature higher, rate of reaction 4.Catalyst added, rate of reaction

60. Problem solving

62. Pattern of graphs Reactant A + Reactant B  gases Less Less More

65. More examples of interpreting graphical results

67. 1. the curves of graph for Magnesium mass against the time Magnesium Excess >>>

68. 2. the curves of graph for hydrochloric acid concentration against the time Hydrochloric acid Limited reactant

69. 3. the curves of graph for magnesium chloride concentration against the time Hydrochloric acid has been used up & reaction stopped

70. 4. the curves of graph for hydrogen gas volume against the time Hydrochloric acid has been used up & reaction stopped

72. Hydrogen Gas / cm 3 Time / s Set 2 Set 1 The number of moles of chemical subtances are same Factor : total of surface area / Particle size

74. Hydrogen Gas / cm 3 Time / s Set 4 Set 3 The number of moles of chemical subtances are same Factor : Concentration

76. Hydrogen Gas / cm 3 Time / s Set 6 Set 5 The number of moles of chemical subtances are same Factor : Concentration

78. Hydrogen Gas / cm 3 Time / s Set 8 Set 7 The number of moles of chemical subtances in Set 8 is higher, so the volume of gas realeased is higher Factor : Concentration

79. 1.3 Collision Theory

85. Activation energy

87. therefore some main ways of increasing the rate of a reaction: 1) increase the number of collisions 2) increase the amount of kinetic energy so that more collisions lead to a reaction 3) decrease the energy activation so that more reactants could be reacted what factors could cause 1, 2, 3?

92. Activation energy Lower Activation energy

94. Conclusion