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CHEM 202 Exam 2 (Dykstra - Fall 16)

Terms in this set (41)

Acid
Electrophile + e- deficient
Base
Nucleophile + e- rich
Electrophile
Positive charge

***arrows point here
Nucleophile
Negative charge or DB

***arrows starts here (lone pair or bond)
The stronger the acid...
The weaker the conjugate base
The weaker the acid...
The stronger the conjugate base
Lower pKa...
Stronger acid
Larger pKa...
Weaker acid
Larger Ka...
Stronger acid
Lower Ka...
Weaker acid
1. The larger the atom attached to H...
The longer the bond = weaker the bond = STRONGER ACID

***size increases top to bottom, left to right
2. The more EN atom attached to H...
The more polarized the bond = STRONGER ACID

***EN increases bottom to top, left to right
sp, sp2, sp3
sp (2), sp2 (3), sp3 (4)

sp = most EN
sp3 = least EN

***lone pairs and DB/TB count as (1)
3. The closer the substituent to H...
STRONGER ACID
4. If conjugate base has a resonance...
The more stable the conjugate base = weaker the conjugate base = stronger conjugate acid = STRONGER ACID
pH > pKa
Acidic (original form)
pH < pKa
Basic (remove proton)
Alcohol
basic = charged (O-)
acidic = uncharged (OH)
Carboxylic Acid
basic = charged (O=CO-)
acidic = uncharged (O=COH)
Amine
basic = uncharged (NH2:)
acidic = charged (NH3+)
Ether dissolves...
Uncharged compounds

***less dense, top layer
Water dissolves...
Charged compounds

***more dense, bottom layer
Nucleophilicity
How fast a nucleophile attacks an e- deficient molecule
1N. The greater the negative charge...
The greater the nucleophilicity
2N. Left to right...
The less the nucleophilicity
3N. Top to bottom...
The greater the nucleophilicity
Carbon charges
3B + 1 lone pair = -
3B + 0 lone pair = neutral
Oxygen charges
2B + 2 lone pairs = neutral
3B + 1 lone pair = +
1B + 3 lone pairs = -
Nitrogen charges
3B + 1 lone pair = neutral
4B + 0 lone pairs = +
2B + 2 lone pairs = -
Formal charge
valence - (lone pairs + bonds)

*** lone pairs and DB count as (2)
Transition State
Maximum energy, no real bonds, not stable
Intermediates
Produced in one step, consumed in the other.

Has bonds and may have formal charge
Basic intermediates
Negative or neutral
Acidic intermediates
Positive or neutral
Catalysts
Speed up reactions by lowering Ea, has real bonds, NOT in overall reaction
The smaller the Ea...
The faster the step
The larger the Ea...
The slower the step
Rate-limiting step
Largest Ea
Gibbs = positive
Favors reactants, ENDERGONIC

***curve ends higher at P
Gibbs = negative
Favors products, EXERGONIC

***curve starts higher at SM
Gibbs formula
G = products - reactants
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