Chapter 3 Flashcards
what is a Bronsted-Lowry Acid?
a Bronsted-Lowry acid is a proton donor
what is a Bronsted-Lowry Base?
a Bronsted-Lowry Base is a proton acceptor
which one is the acid, the base, the conjugate acid, and the conjugate base?
what is a reaction mechanism?
a reaction mechanism is how the reaction occurs in terms of the (real!) motion of electrons
What is Keq? (also formula?)
Keq is the equilibrium constant of a reaction. It describes the moment when the rate of the forward reaction equals the rate of the reverse reaction, in terms of the concentrations of products and reactants.
Keq = [products]
[reactants]
what is Ka? (also formula)
Ka is another way of expressing Keq
Ka = [products]without water
[reactants]
what’s the equation for pKa?
pKa = -log(Ka)
are lower or higher pKa values more acidic?
lower
a stronger acid generates a ___________ conjugate base
weaker
a weaker acid generates a ____________ conjugate base
stronger
a stronger base generates a _________ conjugate acid
weaker
a weaker base generates a ___________ conjugate acid
stronger
the equilibrium of a reaction will always favor the __________ acid
weaker
the equilibrium of a reaction will always favor the ___________ base
stronger
what does this symbol mean?
the position of equilibrium favors the right side
a weaker acid has a _________ pKa value
higher
a stronger acid has a __________ pKa value
lower
reaction equilibrium will favor the side where the pKa (of the acid) is __________
higher
why are some reaction equilibriums written —> or <— ?
because they essentially proceed in only one direction
(because of a vast different in pKa of the acids)
the ___________ base indicates the side the reaction will favor
more stable
a more stable conjugate base indicates a _______ acid, which will drive the reaction _________
stronger
towards the conjugate base
conjugate bases frequently bear a __________ charge (proton ________)
negative
donor
conjugate acids frequently bear a __________ charge (proton ________)
positive
acceptor
How do you determine which base is more stable?
ARIO-S
A: ATOM: more massive atoms bearing a negative charge are more stable
more electronegative atoms bearing a negative charge are more stable
(mass > electronegativity)
R: RESONANCE: resonance makes more stable
I: INDUCTION: induction from nearby electronegative atoms makes a base more stable
O: ORBITAL: smaller orbitals are more stable when bearing an electron
S: STERICALLY HINDERED: the less bulky (# of different connections) base is more stable
a Lewis acid is an ____________
electron acceptor
a Lewis Base is an ___________
electron donor
when do we use Lewis acids/bases?
to discuss acid-base reactions that do not involve hydrogen as an active part of the reaction
which base is more stable?: explain A
a more massive atom can distribute the - charge over the whole atom, making it more stable
mass > (dominant effect) electronegativity
a more electronegative atom is more stable when bearing a - charge (electron)
which base is more stable?: explain R
resonance structures are more stable because the charges are delocalized (spread out over entire molecule)
which base is more stable?: explain I
induction from nearby (highly electronegative) atoms helps to create a more stable base
electronegative atoms induce a stronger partial charge, helping to make the area near the electron more positive, so that it can hold the electron more strongly
which base is more stable?: explain O
smaller orbitals are more stable when bearing an electron because the electron’s orbital is closer to the nucleus
which base is more stable?: explain S
the less bulky base is more stable
the less bulky (less sterically hindered) based can accommodate more solvent reactions and is therefore more stable
(tert-butanol is more bulky)
define sterically hindered
a sterically hindered compound can accommodate fewer solvent reactions
sterically hindered –> less stable
(tert-butanol is more sterically hindered)
