Chapter 13 Chemical Kinetics
description
Transcript of Chapter 13 Chemical Kinetics
![Page 1: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/1.jpg)
Chapter 13Chemical Kinetics
2008, Prentice Hall
Chemistry: A Molecular Approach, 1st Ed.Nivaldo Tro
Roy KennedyMassachusetts Bay Community College
Wellesley Hills, MA
![Page 2: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/2.jpg)
Tro, Chemistry: A Molecular Approach 2
Catalysts• catalysts are substances that affect the rate of a reaction
without being consumed• catalysts work by providing an alternative mechanism
for the reactionwith a lower activation energy
• catalysts are consumed in an early mechanism step, then made in a later step
mechanism without catalyst
O3(g) + O(g) 2 O2(g) V. Slow
mechanism with catalyst
Cl(g) + O3(g) O2(g) + ClO(g) Fast
ClO(g) + O(g) O2(g) + Cl(g) Slow
![Page 3: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/3.jpg)
Tro, Chemistry: A Molecular Approach 3
Ozone Depletion over the Antarctic
![Page 4: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/4.jpg)
Tro, Chemistry: A Molecular Approach 4
Energy Profile of Catalyzed Reaction
polar stratospheric clouds contain ice crystals that catalyze reactions that release Cl from atmospheric chemicals
![Page 5: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/5.jpg)
Tro, Chemistry: A Molecular Approach 5
Catalysts• homogeneous catalysts are in the same phase
as the reactant particlesCl(g) in the destruction of O3(g)
• heterogeneous catalysts are in a different phase than the reactant particlessolid catalytic converter in a car’s exhaust system
![Page 6: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/6.jpg)
Tro, Chemistry: A Molecular Approach 6
Types of Catalysts
![Page 7: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/7.jpg)
Tro, Chemistry: A Molecular Approach 7
Catalytic HydrogenationH2C=CH2 + H2 → CH3CH3
![Page 8: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/8.jpg)
Tro, Chemistry: A Molecular Approach 8
Enzymes
• because many of the molecules are large and complex, most biological reactions require a catalyst to proceed at a reasonable rate
• protein molecules that catalyze biological reactions are called enzymes
• enzymes work by adsorbing the substrate reactant onto an active site that orients it for reaction
![Page 9: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/9.jpg)
Tro, Chemistry: A Molecular Approach 9
Enzyme-Substrate BindingLock and Key Mechanism
![Page 10: Chapter 13 Chemical Kinetics](https://reader036.fdocuments.net/reader036/viewer/2022062323/5681636a550346895dd443d3/html5/thumbnails/10.jpg)
Tro, Chemistry: A Molecular Approach 10
Enzymatic Hydrolysis of Sucrose