The document discusses factors that affect the rate of chemical reactions including temperature, concentration, surface area, and the use of catalysts. It explains how increasing temperature, concentration, or surface area increases the frequency of particle collisions, leading to a faster reaction rate. Catalysts provide an alternative reaction pathway with lower activation energy, allowing more particles to have sufficient energy for reaction. Examples are provided of calculating reaction rates from graphs and sketching how rate curves would change with different conditions.

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

2. AVERAGE RATE OF REACTION For the whole exp From X min to Y min On the X min (2 nd ) ( from 2 nd to 1 st ) For first x (3) min ( from 0 to 3rd )

3. b) Example from the graph, determine: i) The average rate of reaction for the whole experiment = Total volume of gas Total time taken

4. = 46 = 0.20 cm 3 s -1 210

5. b) Example from the graph, determine: i) The average rate of reaction from 3 minute to 1 minute = Total volume of gas at 3min -1 min Total time taken at 3min -1min

6. = 44-25 = 0.13 cm 3 s -1 180-60

7. b) Example from the graph, determine: i) The average rate of reaction for on the 3 rd minute= Total volume of gas at 3min – at 2min Total time taken at 3min – at 2 min

8. = 44-38 = 0.10 cm 3 s -1 180-120

9. b) Example from the graph, determine: i) The average rate of reaction for for the first 2 minutes= Total volume of gas at 2min – at 0min Total time taken at 2min – at 0 min

10. = 38-0 = 0.33 cm 3 s -1 120-0

11. INSTANTANEOUS RATE OF REACTION ( rate of reaction at that time) Draw tangent to the graph Y X Rate = Y/X

12. b) Example from the graph, determine: i) The rate of reaction at 120 s Instantaneous rate of reaction = Draw tangent to the graph

13. = 56 – 20 = 0.176 cm 3 s -1 222-18

17. II I III Volume of gas Time decrease temperature Decrease TSA Decrease conc but not the mole of reactant Use positive catalyst Increase temperature Increase total surface area (TSA) Increase conc but not the mole of reactant

18. Example: Sketch curve that would be obtained with the changes below: original Lower temp Volume of gas Time Lower temperature is used

19. Example: Sketch curve that would be obtained with the changes below: original higher temp Volume of gas Time Higher temperature

20. Example: Sketch curve that would be obtained with the changes below: original Bigger size Volume of gas Time Bigger size of reactant is used

21. Example: Sketch curve that would be obtained with the changes below: original Smaller size Volume of gas Time Smaller size of reactant

22. Example: Sketch curve that would be obtained with the changes below: original higher temp Volume of gas Time Higher temperature

23. Example: Sketch curve that would be obtained with the changes below: original With catalyst Volume of gas Time Catalyst was added

24. Changes to the FLAT part of graph

25. Example: Curve I represents the result of the experiment using excess zinc powder and 50cm 3 of 1.0 moldm -3 dilute hydrochloric acid I Volume of gas/ cm 3 Time/s

26. Draw curves when condition change: ORIGINAL: 50cm 3 of 1.0 moldm -3 dilute hydrochloric acid Change : 50cm 3 of 2.0 moldm -3 dilute hydrochloric acid ori Volume of gas/ cm 3 Time/s Change

27. Draw curves when condition change: ORIGINAL: 50cm 3 of 1.0 moldm -3 dilute hydrochloric acid Change : 50cm 3 of 0.5 moldm -3 dilute hydrochloric acid ori Volume of gas/ cm 3 Time/s Change

28. Draw curves when condition change: ori :50cm 3 of 1.0 moldm -3 dilute hydrochloric acid change : 50cm 3 of 0.5 moldm -3 dilute hydrochloric acid ori Volume of gas/ cm 3 Time/s change

29. Draw curves when condition change: ORI : 50cm 3 of 1.0 moldm -3 dilute hydrochloric acid change : 20cm 3 of 1.0 moldm -3 dilute hydrochloric acid ori Volume of gas/ cm 3 Time/s change

30. Draw curves when condition change: ori: 50cm 3 of 1.0 moldm -3 dilute hydrochloric acid change: 25cm 3 of 2.0 moldm -3 dilute hydrochloric acid ori Volume of gas/ cm 3 Time/s change

31. 1. The effect of size of reactant Reducing the size of reactant increases the Total Surface Area increases the frequency of collisions between particles Increase the rate of reaction . Increase the frequency effective collisions between particles

32. 2. The effect of temperature Increase the temperature of solution increase the kinetic energy of particles increase the frequency of collisions between particles Increase the rate of reaction . Increase the frequency effective collisions between particles

33. 3. The effect of concentration Increase the concentration of solution increase the number of particles per unit volume increase the frequency of collisions between particles Increase the rate of reaction . Increase the frequency effective collisions between particles

34. 4. The effect of catalyst Catalyst provides alternative route That has a lower activation energy Increase the rate of reaction . So more particles have energy equal or greater than activation energy . Number of effective collisions increase .

35. exothermic reaction

36. Activation energy with catalyst Activation energy no catalyst reactant

37. Write chemical equation ( 9m) Calcium carbonate and hydrochloric acid ( 2m)

38. Write chemical equation ( 9m) Sodium thiosulphate and sulphuric acid( 2m)

39. Write chemical equation ( 9m) Decomposition of hydrogen peroxide ( 2m)

40. What is the catalyst used in the decomposition hydrogen peroxide?(1m) Manganese (IV) oxide

41. Write ionic equation for Sodium thiosulphate and sulphuric acid (2m)

42. End