Rates of Chemical Reactions

1. Rates of Chemical Reactions Chapter 6

3. Things that Affect Rate • Temperature • Higher temperature faster particles. • More and harder collisions. • Faster Reactions. • Concentration • More concentrated closer together the molecules. • Collide more often. • Faster reaction.

4. Things that Affect Rate • Particle size • Molecules can only collide at the surface. • Smaller particles bigger surface area. • Smaller particles faster reaction. • Smallest possible is molecules or ions. • Dissolving speeds up reactions. • Getting two solids to react with each other is slow.

5. Things that Affect Rate • Catalysts- substances that speed up a reaction without being used up.(enzyme). • Speeds up reaction by giving the reaction a new path. • The new path has a lower activation energy. • More molecules have this energy. • The reaction goes faster. • Inhibitor- a substance that blocks a catalyst.

23. AP enrichment

27. AP enrichment

28. AP enrichment

35. H2 + O2 H2O Reactants Energy Products Reaction coordinate

36. Activation Energy - Minimum energy to make the reaction happen Reactants Energy Products Reaction coordinate

37. Activated Complex or Transition State Reactants Energy Products Reaction coordinate

38. Reactants Energy Overall energy change- ∆H Products Reaction coordinate

47. H H H H H H H H Catalysts- heterogeneous gas and solid • Hydrogen bonds to surface of metal. • Break H-H bonds Pt surface

48. H H C C H H H H H H Catalysts Pt surface

49. H H H H C C H H H H Catalysts • The double bond breaks and bonds to the catalyst. Pt surface

50. H H H H C C H H H H Catalysts • The hydrogen atoms bond with the carbon Pt surface