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Unit 7: Kinetics. Microscale Kinetics Day 2. Unit 7: Kinetics. More on Catalysts. Catalysts speed up reaction rates, how?. cis-2-butene converts to trans-2-butene. I 2. Cis-2-butene. Unit 7: Kinetics. More on Catalysts. Catalysts speed up reaction rates, how?.
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Unit 7: Kinetics Microscale Kinetics Day 2
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics More on Catalysts Catalysts speed up reaction rates, how? cis-2-butene converts to trans-2-butene I2 Cis-2-butene Step 1: I2 dissociates Step 2: I attaches to C breaking the double bone Catalyst Step 3: Single bond is now free to rotate Intermediate Step 4: Iodine is removed and double bond reforms Product
Unit 7: Kinetics Reaction Mechanisms: The sequence of bond-making and bond breaking steps that occur during a reaction. Refer back to the cis to trans conversion of butene… I2
Unit 7: Kinetics Reaction Mechanisms: The sequence of bond-making and bond breaking steps that occur during a reaction. Br2 + 2 NO 2 BrNO What would it take for this to be a single step reaction??? (Think collision theory) Br2 NO NO Since this is unlikely, the following mechanism is proposed …
Unit 7: Kinetics Molecularity of Mechanism Steps: The decomposition of ozone: 2 O3 3 O2 Termolecular and beyond:
Unit 7: Kinetics Rates of Mechanism Steps: Each individual step has its own rate, and therefore its own rate law. Stoichiometry can only be used to write rate laws for mechanism steps!!! (NOT OVERALL REACTIONS)
Unit 7: Kinetics Practice Problem: 3 ClO- ClO3- + 2Cl- Proposed mechanism: Step 1: Pt + 2 ClO- PtClO2-+ Cl- Step 2: PtClO2- + ClO- Pt + ClO3- + Cl- a. What is the molecularity of each step? b. Write the rate equation for each step? c. Show that the sum of the steps gives the overall reaction. d. Identify any catalysts and/or intermediates present.
Unit 7: Kinetics Sample AP Multiple Choice: The energy diagram for R P is shown above. The addition of a catalyst to this reaction would cause a change in which of the indicated energy differences? I II III • I only • II only • III only • I and II only • I, II and III