Final Flashcards
chpt 1
HONC
Hydrogen 1
Oxygen 2
Nitrogen 3
Carbon 4
number of bonds to be neutral
chpt 1
What molecules perform hydrogen bonding?
NOF
chpt 1
Constructive interference
produces a bonding MO + larger wave amplitude
waves have effective overlap
chpt 1
Destructive interference
creates an anti bonding MO, or a node
waves do not have overlap
chpt 1
Orbitals are — in MO theory
conserved, the number you start with is the number you will end with
chpt 1
HOMO
highest energy occupied molecular orbital
chpt. 1
LUMO
lowest energy unoccupied molecular orbital
chpt 1
How many unhyridized p orbitals are there on an sp3 hybridized molecule?
0, 1 S orbital with 3 p orbitals
chpt 1
how many orbitals are formed in an sp2 hybridized molecule
3 orbitals
one unhybiridzed p orbital
chpt 1
what kind of orbitals overlap to form sigma bonds?
hybridized orbitals
chpt 1
what kind of bonds overlap to form pi bonds?
unhybridized
chpt 2
if a carbon has a - charge what is attatched to it?
three bonds and a lone pair
sp3 hybridized
chpt 2
if a carbon has a + charge what is attatched to it?
three bonds and no electrons
sp2 hybridized
chpt 2
localized electrons
e- that do not participate in resonance, if they cannot participate they are localized
chpt 2
delocalized electrons
e- that can participate in resonance
chpt 2
True or false? if you have a molecule that has lone pairs + a pi bond both will participate in resonance
false, the pi bond will participate, not the lone pairs
chpt. 2
How do you determine the most significant resonance structure?
- one with no charge will be the most significant
- if there are charges, the one with the fewest charges is most significant
- the structure with a negative charge on the most electronegative atom is most significant
stability = significance
chpt 3
Bronsted Lowry Acid
proton donor
chpt 3
Bronsted Lowry base
proton acceptor
chpt 3
acids will not lose a proton without a — present
base
chpt 3
explain the proton transfer mechanism
two arrows, one arrow from the atom to be protonated to the hydrogen and one arrow from the bond connecting the hydrogen to the connecting molecule
chpt 3
curved arrows start at places of — —
electron density
chpt 3
the — the pka value the stronger the acid
lower
chpt 3
strong acids create — bases
weak
chpt 3
CARIO
Charge
Atom
Resonance
Induction
Ortbials
weak is winner!
chpt 3
explain charge in CARIO
the neutral atom will be more stable than a charged atom
bases will likely be negative or neutral
chpt 3
Explain Atom in CARIO
a more electronegative atom with a charge will stabilize better
chpt 3
In the choice between S- and O- in CARIO which one would you choose?
you would choose S because if atoms are in the same colum the larger one is more stable
same row = electronegativity
chpt 3
explain resonace in CARIO
a charged atom stabilized by resonace will be more stable than one without resonance
delocalization stabilizes
chpt 3
Explain induction in CARIO
more electronegative atoms (like halogens) will stabilize a negative charge, the more electronegative atoms the better
the closer it is the better
chpt 3
explain Orbitals in CARIO
the more s character the better
sp>sp2>sp3
chpt 3
Which is the more stable base? NH2 or terminal alkyne?
this is an exception! a terminal alkyene is more stable than an amine
chpt 3
Lewis Acid
electron pair acceptor
chpt 3
Lewis base
electron pair donator
chpt. 4
Newman Projection
used to view a front and back carbon of a molecule
chpt. 4
staggard conformation
lower E, angles between groups are equal
chpt. 4
eclipsed conformation
high E, groups are close together likely creating strain
chpt. 4
Torsional strain
twisted, only occurs with ecplised conformations
chpt 4
steric strain
can occur in staggard and ecplised conformations where two groups that are not hydrogens interact
chpt 4
gauche conformation
staggard conformation with steric strain
chpt 4
what is the most stable conformation of cyclohexane?
chair conformation, no strain
chpt 4
every cyclohexane can have a max of – chair conformations
two
chpt. 4
True or false? after a ring flip the substiuents direction and position change
false, positon changes but not direction
if its up then its up if its down then its down
chpt 4
the most stable conformation will be one with all equitorial positions or ——
with the largest groups in equitorial positions
chpt. 5
Constiutional Isomers
same formula, different connectivity
chpt 5
stereoisomers
same formula, same connectivity, different spatial arrangments
different wedges and dashes
chpt 5
what does it mean to be chiral?
to be non superimposable on your mirror image
achrial= you can super impose
chpt 5
chiral center
a carbon with four different groups attatched
chpt 5
stereocenter
an atom where swapping two groups produces a stereoisomer of the atom
often sp2 atoms attatched to double bonds
chpt 5
enantiomer
the mirror image of a molecule
chpt 5
if you see a molecule that has been flipped across a mirrored surface and the wedges and dashes have also been flipped what is its relationship to the original molecule?
It is an identical molecule, if you do both options it creates an identical molecule
chpt 5
Steps to designating R and S
1, find the chiral center
2. assign priority 1-4 to the four groups
3. is the 1st group wedged forward? is the fourth group dashed back? If not you will count 1-3 and then switch your answer to the oppostie of what you got
chpt 5
what does it mean to optically active?
to be able to rotate a plane of polarized light
chpt 5
enantiomers will rotate light in equal but —–
opposite directions
chpt 5
how do you assign E and Z?
- assign priority to one of the two groups on either side of alkene
- if the higher priority groups are on the same side = Z
- if the higher priority groups are on the oppostie side = E
chpt 5
any compound with a plane of symmetry will be —
-or no chiral center
Achiral
chpt 5
How do you determine the number of stereoisomers in a molecule?
2^n where n= number of chiral centers
- subtract 1 if there is a plane of symmetry
- count two stereocenters on either side of a pi bond as 1
- draw out possible stereoisomers
chpt 6
enthalpy
the change in heat from reactants to products in a reaction
chpt 6
what is the favorable sign for H (enthalpy)?
a negative H sign = an exothermic reaction= favorable
a positive H sign= endothermic reaction = non favorable
chpt 6
entropy
the amount of disorder in a system
chpt 6
what is the favorable sign for entropy?
a positive entropy = favorbale
a negative entropy = non favorable
chpt 6
what sign of gibbs free energy indicates a spontaneous reaction?
a negative G indicates a spontaneous reaciton
chpt 6
exergonic
spontaneous, negative G, reactants are higher in E than products
chpt 6
endergonic
non spon, positive g, products are higher in E than reactants