Organic Chemistry Chapter 4

Front 1

Halogenation only works on what hybridization?

Back 1

sp^3 hybridized carbons

Front 2

What elements does halogenation work best with?

Back 2

Cl and Br
Which one is more selective?
Why not I or F?

Hint 2

Bromine
Iodine = too slow
Fluorine = too fast (blows up)

Front 3

Initiation of halogenation?

Back 3

homolytic cleavage of X2
means?

Hint 3

one molecule (ex. Cl2) splits into two radicals (Cl- and Cl-)

Front 4

Three steps of rxn?

Back 4

Initiation, Propagation, Termination

Front 5

Propagation in halogenation?

Back 5

start with one molecule and one radical, end up with one molecule and one radical

Front 6

Termination in halogenation?

Back 6

Any two radicals stick together

Front 7

What are carbocations?

Back 7

sp2 hybridized carbons
3 bonds, no lone pairs (empty p orbital)

Stability?

Hint 7

More carbons attached to carbocation make it more stable

Front 8

What is the only intermediate that can undergo rearrangement?

Back 8

1° carbocation with 3° carbocation next door

**What to think**

Hint 8

See: carbocation intermediate
**!Carbocations can rearrange!**

Front 9

What are carbon radicals?

Back 9

3 bonds, 1 unpaired electron
electron deficient (they want the full bond)

Geometry?
Stability?

Hint 9

trigonal planar, sp2 hybridized
only 1 electron in p orbital

3°>2°>1°>CH3 --->MORE stable when connected with more carbons

Front 10

Ranking of carbons with charges..

Back 10

carbocations (+)
carbon radicals (e-deficient)(neutral)
carbenes (neutral)
carbon anions (-)

Front 11

What are carbenes?

Back 11

2 bonds, 1 lone pair (rare)
Neutral, sp2 hybridized with empty p-orbital

electrophile or nucleophile?

Hint 11

either

Front 12

What stabilizes carbocations, radicals, and carboanions?

Back 12

resonance!
example: 1 away from a double bond is? 1 away from an aromatic ring is?

Hint 12

1 away from
double bond=allylic
aromatic ring=benzylic

Front 13

What is particularly unstable?

Back 13

to have a charge on directly on an aromatic ring, what is this called?

Hint 13

aryl = particularly unstable

Front 14

If a rxn is HIGHLY exergonic, K(eq) should be...
If a rxn is HIGHLY endergonic, K(eq) should be ...

Back 14

highly exergonic K(eq) >10^3
highly endergonic K(eq) < 10^-3

Front 15

∆G = ?

Back 15

∆G=∆H-T∆S
exergonic when?
endergonic when?
spontaneous or not?

Hint 15

exergonic when ∆G<0, spontaneous
endergonic when ∆G>0, NOT spontanious

Front 16

Bond Dissociation Energies (change in HEAT)
When is it exothermic? endothermic?

Back 16

exothermic: ∆H<0
endothermic: ∆H>0
estimating ∆H?

Hint 16

estimate ∆H by (bonds broken) - (bonds formed)

Front 17

Kinetics = rate of reaction formula

Back 17

For A+B → C+D
Rate = k[A]^m[B]^n
Rate determined by your reactants

Front 18

Transition states

Back 18

chemical species which exist fleetingly, bonds are breaking/forming all at once here
at the peaks of a rxn coordinate diagram

Front 19

Intermediates

Back 19

These occur at the troughs of a rxn coordinate diagram, exist long enough to be isolated ("fleetingly" does NOT describe these)

Front 20

On a rxn coordinate diagram...
The number of humps are?
The valleys are?
The top of the humps are?
The highest hump is?

Back 20

# of humps = # of steps
valleys = intermediates
hump tops = transition states (TS)
highest hump = rate determining step