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Chemical Kinetics Roshini Ramachandran Learning Outcomes Students - - PowerPoint PPT Presentation
Chemical Kinetics Roshini Ramachandran Learning Outcomes Students - - PowerPoint PPT Presentation
Chemical Kinetics Roshini Ramachandran Learning Outcomes Students will be able to: 1. Predict the effect of reaction temperature on the rate of a chemical reaction. 2. Interpret a graph plotted between rate of a chemical reaction and
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Topics covered to date
Students have learned:
- 1. Rates, Rate Constants, Order of reactions
- 2. Differential and Integrated Rate Laws
- 3. Activation Energy & Arhennius’ Equation
- 4. Effect of reactant concentration on rate
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Recap: Effect of concentration
Red dye + bleach Colorless product
Rate = -d[dye]/dt = k[dye]m [bleach]n
INSERT CLICKER QUESTION ON THE EFFECT OF REACTANT CONCENTRATION ON THE RATE OF A CHEMICAL REACTION
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Effect of temperature
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Clicker Question
Increasing the temperature of a reaction increases its reaction rate. A) Yes B) No C) Cannot say
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INSERT IMAGE OF NEWS ARTICLE/TITLE FROM https://www.cbsnews.com/news/florida-frozen- iguanas-falling-from-trees-during-cold-snap-bomb- cyclone-storm-east-coast/ INSERT IMAGE OF NEWS ARTICLE/TITLE FROM https://www.cbsnews.com/news/effort-to-save-cold- stunned-sea-turtles-cold-weather/
Case Study Worksheet: Class Discussion
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Cold-blooded animals & temperature
Body temperature depends on surroundings
Thermal Image of reptile INSERT THERMAL IMAGE OF LIZARD FROM http://coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/lizard.html
(I use http://coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/images/lizard3_ir.jpg)
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Case Study Worksheet: Class Discussion Food for thought:
Identify one potential method to save these animals
(Discuss in your groups)
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Recap: Collision Theory
It is only collisions that possess at least the activation energy for the reaction which result in a reaction
Image credit: Tro NJ, Fridgen T, Shaw L. 2010. Chemistry: A Molecular Approach, 2nd US edition. Pearson.
IMAGE OF THERMALLY ENERGETIC COLLISIONS Recommended: Figure 14.15, pg. 611 Tro NJ, Fridgen T, Shaw L. 2010. Chemistry: A Molecular Approach, 2nd US edition. Pearson. IMAGE OF BOLTZMANN DISTRIBUTION OF MOLECULAR ENERGIES Recommended: Figure 14.14, pg. 608 Tro NJ, Fridgen T, Shaw L. 2010. Chemistry: A Molecular Approach, 2nd US edition. Pearson.
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Rate and Rate constant
Factors affecting rate?
Ans: Concentration, Temperature
Arhennius Equation: k = Ae– Ea/RT Factors affecting rate constant?
Ans: Temperature
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Catalysts
IMAGE OF REACTION ENERGY DIAGRAM FOR A CHEMICAL REACTION WITH A CATALYST Recommended: Figure 14.17, pg. 619 Tro NJ, Fridgen T, Shaw L. 2010. Chemistry: A Molecular Approach, 2nd US edition. Pearson.
- Alters the rate of a reaction by providing an
alternate pathway with lower activation energy.
- Participates
in a reaction by forming an intermediate, but is regenerated.
NO (catalyst) 2SO2 + O2 2SO3 Mechanism: i. 2NO + O2 2NO2 ii. NO2 + SO2 SO3 + NO
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Enzymes
- Enzymes are biological catalysts that enhance reaction
rates.
- Almost all enzymes are proteins, and contain active
sites that can bind to a substrate.
- They are highly specific to their substrates and catalyze
- nly one type of chemical reaction.
IMAGE OF ENZYME-SUBSTRATE BINDING Recommended: Figure 14.21, pg. 622 Tro NJ, Fridgen T, Shaw L. 2010. Chemistry: A Molecular Approach, 2nd US edition. Pearson.
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IMAGE OF EFFECT OF TEMPERATURE ON AN ENZYME CATALYZED REACTION VS SIMPLE CHEMICAL REACTION http://www.bbc.co.uk/staticarchive/199acbfe2bac854818 d719d6ce0e53e4cd3cd5d2.gif