Ch. 4: Analyzing Organic Reactions Flashcards
an acid-base reaction will proceed so long as what is more reactive than what
as long as reactants are more reactive/stronger than the products
Lewis acids are electron…
electron acceptors in the formation of a covalent bond. Tend to be electrophiles
Lewis bases are electron…
electron donors in the formation of a covalent bond. Tend to be nucleophiles.
lewis acids and bases form what kind of covalent bonds
coordinate covalent bonds, in which both electrons come from the same starting atom (the Lewis acid)
amphoteric
ability to act as either Bronsted-Lowry acids or bases
Bronsted-Lowry acids are proton…
proton donors (H+)
Bronsted-Lowry bases are proton…
acceptors
acid dissociation constant, Ka, measures
strength of an acid in solution
Ka = …
Ka = [H+][A-] / [HA]
pKa = …
-log Ka
acidic molecules have what size pKa
small, even negative
basic molecules have what size pKa
large
effect of charge on nucleophile strength
increases with increased electron density/increased negative charge
effect of electronegativity on nucleophilic strength
decreases as EN increases
effect of steric hindrance on nucleophilic strength
decreases as molecules become bulky
effect of solvent on nucleophilic strength
decreases in protic solvents
common nucleophiles
HONC with a minus sign or lone pair
In a polar protic solvent, nucleophilicity increases up/down the periodic table?
increases down the periodic table because down the periodic table are less effected by the protons in solution
I- > Br- > Cl- > F-
In a polar aprotic solvent, nucleophilicity increases up/down the periodic table?
increases up the periodic table because no protons are in the way of attacking the nucleophile
F- > Cl- > Br- > I-
nucleophiles are attracted to…?
nucleus (positive areas of charge) because they are electron/negative charge rich
electrophiles are attracted to…?
electrons (negative areas of charge) because they are positive charge rich
common electrophiles
alcohols, aldehydes and ketones, carboxylic acids (electrophilicity is essentially acidity)
Heterolytic reactions
a bond is broken and both electrons are given to one of the two products
term for which molecular fragment retains electrons after heterolysis
leaving group
what makes for a good leaving group
leaving group will stabilize the extra electrons
I-, Br-, Cl-
SN1 reactions have how many steps
two
- leaving group leaves, generating a carbocation
- nucleophile attacks the carbocation
SUBSTITUTION PRODUCT
Which step of an SN1 reaction is the rate limiting step
step one, the leaving group leaves
SN2 reactions have how many steps
one step
nucleophile attacks the compound at the same time the leaving group leaves
what changes in oxidation-reduction reactions
the oxidation states of the reactants
oxidation
increase in oxidation state,
loss of electrons OR decrease in number of bonds to hydrogen and increase in number of bonds to carbon, nitrogen, oxygen, halides
reduction
decrease in oxidation state, gain of electrons or number of bonds to hydrogen
oxidizing agent
element/compound that accepts electron from another species during a redox reaction
what does it mean to be “reduced”
to accept electrons during an redox reaction, to be an oxidizing agent
oxidizing agents usually contain metals bonded to a large number of what kind of atoms
oxygen atoms
reduction agents usually contain metals bonded to a large number of what kind of atoms
hydrides
