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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
Halogenation only works on what hybridization?
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sp^3 hybridized carbons
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What elements does halogenation work best with?
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Cl and Br
Which one is more selective? Why not I or F? |
Bromine
Iodine = too slow Fluorine = too fast (blows up) |
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Initiation of halogenation?
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homolytic cleavage of X2
means? |
one molecule (ex. Cl2) splits into two radicals (Cl- and Cl-)
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Three steps of rxn?
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Initiation, Propagation, Termination
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Propagation in halogenation?
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start with one molecule and one radical, end up with one molecule and one radical
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Termination in halogenation?
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Any two radicals stick together
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What are carbocations?
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sp2 hybridized carbons
3 bonds, no lone pairs (empty p orbital) Stability? |
More carbons attached to carbocation make it more stable
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What is the only intermediate that can undergo rearrangement?
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1° carbocation with 3° carbocation next door
**What to think** |
See: carbocation intermediate
**!Carbocations can rearrange!** |
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What are carbon radicals?
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3 bonds, 1 unpaired electron
electron deficient (they want the full bond) Geometry? Stability? |
trigonal planar, sp2 hybridized
only 1 electron in p orbital 3°>2°>1°>CH3 --->MORE stable when connected with more carbons |
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Ranking of carbons with charges..
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carbocations (+)
carbon radicals (e-deficient)(neutral) carbenes (neutral) carbon anions (-) |
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What are carbenes?
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2 bonds, 1 lone pair (rare)
Neutral, sp2 hybridized with empty p-orbital electrophile or nucleophile? |
either
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What stabilizes carbocations, radicals, and carboanions?
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resonance!
example: 1 away from a double bond is? 1 away from an aromatic ring is? |
1 away from
double bond=allylic aromatic ring=benzylic |
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What is particularly unstable?
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to have a charge on directly on an aromatic ring, what is this called?
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aryl = particularly unstable
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If a rxn is HIGHLY exergonic, K(eq) should be...
If a rxn is HIGHLY endergonic, K(eq) should be ... |
highly exergonic K(eq) >10^3
highly endergonic K(eq) < 10^-3 |
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∆G = ?
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∆G=∆H-T∆S
exergonic when? endergonic when? spontaneous or not? |
exergonic when ∆G<0, spontaneous
endergonic when ∆G>0, NOT spontanious |
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Bond Dissociation Energies (change in HEAT)
When is it exothermic? endothermic? |
exothermic: ∆H<0
endothermic: ∆H>0 estimating ∆H? |
estimate ∆H by (bonds broken) - (bonds formed)
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Kinetics = rate of reaction formula
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For A+B → C+D
Rate = k[A]^m[B]^n Rate determined by your reactants |
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Transition states
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chemical species which exist fleetingly, bonds are breaking/forming all at once here
at the peaks of a rxn coordinate diagram |
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Intermediates
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These occur at the troughs of a rxn coordinate diagram, exist long enough to be isolated ("fleetingly" does NOT describe these)
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On a rxn coordinate diagram...
The number of humps are? The valleys are? The top of the humps are? The highest hump is? |
# of humps = # of steps
valleys = intermediates hump tops = transition states (TS) highest hump = rate determining step |
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