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exam 1
ch.1-5 conceptual
36
Organic Chemistry
Undergraduate 2
10/24/2012

Additional Organic Chemistry Flashcards

 


 

Cards

Term
between what atoms will you find perfect (covalent) sharing of electrons?
Definition
only between two of the same atoms (i.e. H2)
Term
ionic character
Definition
when electron sharing between atoms is unequal and they are more strongly drawn to one atom above the other
Term
inductive effect
Definition
shifting of electrons in a bond toward the more electronegative of the nearby atoms
Term
delocalized electron
Definition
a PI or NONBONDING electron that can be in different places on a molecule - RESONANCE STRUCTURES
Term
acetone
Definition
[image]
Term
Bronsted-Lowry acid/base
Definition

acid: donates H+ in solution

 

base: accepts H+ in solution

Term
acetic acid
Definition
[image]
Term
a strong acid has a __________ Ka and a ________ pKa
Definition
a strong acid has a HIGH Ka and a SMALL pKa
Term

from left ---> right across the periodic table, the atoms will be _________ stable (re: being acidic)

 

from down ^ up on the periodic table, the atoms will be ___________ stable

Definition

----> MORE stable (stronger acid)

 

^ LESS stable (weaker acid; stronger acid as you increase in size)

Term
S-H is [more/less] acidic than O-H
Definition
S-H is MORE reactive!
Term
why are multiple bonds more stable? (i.e. a hydrogen attached to them will be more acidic)
Definition
S orbitals are low in energy; the smaller the amount of hybidization, the greater % of S-orbital they have in them; low energy is more stable.
Term
three types of Lewis acids
Definition

1. metal cations (can accept electron pair)

 

2. compounds with unfilled valence shells/orbitals

 

3. electrophiles (organic compounds that like electrons)

Term

Lewis bases [are/are not] also Bronsted-Lowry bases. Why/why not?

 

Lewis acids [are/are not] also Bronsted-Lowry acids. Why/why not?

Definition

Lewis bases (donate an electron pair) can accept hydrogens too - they ARE also Bronsted bases.

 

Lewis acids don't always have a hydrogen in them! So they often aren't also Bronsted bases.

Term
alkanes are relatively inert, but they react with _________ and _________
Definition
they react with HALOGENS and OXYGEN
Term
London dispersion forces
Definition
intermolecular, noncovalent interactions between temporary "induced" dipoles
Term

Boiling point and melting point go [up/down] with more carbons in alkanes?

 

Boiling point and melting point go [up/down] with more branching in alkanes?

 

Why?

Definition

with more carbons, intermolecular forces are stronger, so BP and MP go UP

 

but there's less surface area with more branching, so BP and MP go DOWN

Term
torsional strain vs. steric strain
Definition
torsional strain is the repulsion of bonds; steric strain is the repulsion between atoms
Term
Hund's Rule
Definition
empty orbitals are filled [with electrons] first
Term
Aufbau principle
Definition
lowest-energy orbitals fill first
Term
bonds break spontaneously if....
Definition
the PRODUCTS are more stable than the REACTANTS
Term
what is wrong with this sentance: "The pi bonding molecular orbital in thylene results from sideways overlap of two p atomic orbitals."
Definition
missing the fact that they have to be p orbitals OF THE SAME SIGN.
Term
isoelectric relationship
Definition
two molecules that have the same number of electrons
Term
a pair of mirror image molecules that are not identical to one another
Definition
enantiomers
Term
molecules that exist in two enantiomeric forms
Definition
CHIRAL molecules
Term
what causes a molecule's chirality?
Definition
a chirality center
Term
optically active molecule
Definition
a molecule (ALWAYS chiral) that rotates the plane of polarization of any polarized light that is shone through it
Term
on what four factors does optical activity (degree of rotation) depend?
Definition

1. heat

2. path length

3. concentration

4. wavelength

Term
what are the three factors which could make the net rotation of a compound zero?
Definition

- if the molecule is inactive

- or equal amounts of enantiomers are present

- or the molecule is meso

Term
generally, a molecule with n chirality centers can have how many stereoisomers?
Definition
2n
Term
diastereomers
Definition
stereoisomers that are NOT mirror images
Term
epimers
Definition
diastereomers that only differ by one chirality center
Term
a compound that is achiral and still contains chirality centers
Definition
Term
racemic mixture
Definition
mixture containing equal amounts of each enantiomer (reducing optical activity to zero)
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