Содержание
- 2. INTRODUCTION This Powerpoint show is one of several produced to help students understand selected topics at
- 3. RATES OF REACTION CONTENTS Prior knowledge Collision Theory Methods for increasing rate Surface area Temperature Catalysts
- 4. Before you start it would be helpful to… know how the energy changes during a chemical
- 5. CHEMICAL KINETICS Introduction Chemical kinetics is concerned with the dynamics of chemical reactions such as the
- 6. COLLISION THEORY Collision theory states that... particles must COLLIDE before a reaction can take place not
- 7. COLLISION THEORY Collision theory states that... particles must COLLIDE before a reaction can take place not
- 8. INCREASING THE RATE INCREASE THE SURFACE AREA OF SOLIDS INCREASE TEMPERATURE SHINE LIGHT ADD A CATALYST
- 9. INCREASING SURFACE AREA Increases chances of a collision - more particles are exposed Powdered solids react
- 10. Effect increasing the temperature increases the rate of a reaction particles get more energy so can
- 11. INCREASING TEMPERATURE According to KINETIC THEORY, all particles must have energy; the greater their temperature, the
- 12. Experiments showed that, due to the many collisions taking place between molecules, there is a spread
- 13. Increasing the temperature alters the distribution get a shift to higher energies/velocities curve gets broader and
- 14. Decreasing the temperature alters the distribution get a shift to lower energies/velocities curve gets narrower and
- 15. REVIEW no particles have zero energy/velocity some particles have very low and some have very high
- 16. Ea ACTIVATION ENERGY - Ea The Activation Energy is the minimum energy required for a reaction
- 17. Explanation increasing the temperature gives more particles an energy greater than Ea more reactants are able
- 18. Catalysts provide an alternative reaction pathway with a lower Activation Energy (Ea) Decreasing the Activation Energy
- 19. The area under the curve beyond Ea corresponds to the number of molecules with sufficient energy
- 20. The area under the curve beyond Ea corresponds to the number of molecules with sufficient energy
- 21. work by providing an alternative reaction pathway with a lower Activation Energy using catalysts avoids the
- 22. work by providing an alternative reaction pathway with a lower Activation Energy using catalysts avoids the
- 23. Catalysts are widely used in industry because they… CATALYSTS - WHY USE THEM?
- 24. Catalysts are widely used in industry because they… allow reactions to take place at lower temperatures
- 25. Catalysts are widely used in industry because they… allow reactions to take place at lower temperatures
- 26. Catalysts are widely used in industry because they… allow reactions to take place at lower temperatures
- 27. Catalysts are widely used in industry because they… allow reactions to take place at lower temperatures
- 28. Catalysts are widely used in industry because they… allow reactions to take place at lower temperatures
- 29. Catalysts are widely used in industry because they… allow reactions to take place at lower temperatures
- 30. shining a suitable light source onto some reactants increases the rate of reaction the light -
- 31. increasing the pressure forces gas particles closer together this increases the frequency of collisions so the
- 32. Increasing concentration = more frequent collisions = increased rate of reaction INCREASING CONCENTRATION However, increasing the
- 33. Reactions are fastest at the start and get slower as the reactants concentration drops. In a
- 34. Experimental Investigation the variation in concentration of a reactant or product is followed with time the
- 35. RATE How much concentration changes with time. It is the equivalent of velocity. MEASURING THE RATE
- 36. REVISION CHECK What should you be able to do? Recall and understand the statements in Collision
- 37. You need to go over the relevant topic(s) again Click on the button to return to
- 38. WELL DONE! Try some past paper questions
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