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UNIT 14 rates - Coggle Diagram
UNIT 14 rates
MISC:
k just expresses the rate of that given reaction; changes with temperature, or nature of the reaction. ALWAYS PUT UNITS OF K; solve for units w/dimensional analysis and rate law
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If coefficients DONT match orders, must be multiple steps..
Best catalyst will actually allow reaction to proceed at lowest temp; if Ea is lower, required energy will be lower
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Types of Catalysts
- Homogeneous catalysts: same state as reactants, form intermediates?
CATALYST is present at beginning (and end; next beginning) while intermediate is created in the middle and used in the middle.
- Surface catalysts: use adsorption to bring molecules together, allowing for opportunities to collide. (usually metal or metal oxide). Use unpaired electrons on metal.
- Acid-Base: donates/accepts a proton from reactant, easing reaction.
- Enzymes, form enzyme-substrate complex, biological molecules
GRAPHS:
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Peak is "activation complex", then it changes form, going down energy gradient
change from beginning to highest point is Ea, change from beginning to end is change in E
Higher peak/Ea means SLOWER, more energy-demanding reaction
LOOK FOR AXES; If it is linear, just concentration is 0, ln[A] is 1st order, 1/[A] is 2nd order
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WHY? Collision Theory
Collision theory: 1. Reactions happen with (more) collisions, 2. Reactants need enough energy when colliding, (> Ea) 3. and correct orientation
SO THINK, these will raise rate:
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Smaller, simpler molecules (less chances for orientation to go wrong)
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