Mcat Organic Chemistry

Front 1

sp hybridization

Back 1

1s and 1p,
50% s character,
50% p character,
linear,
180 degree angles,
2 attached atoms/lone pairs

Front 2

sp2 hybridization

Back 2

1 s, 2 p
33%s character, 67% p character
trigonal planar,
120 degree angles,
3 attached atoms/lone pairs

Front 3

sp3 hybridization

Back 3

1s 3 p
25% s character, 75%p character, tetrahedral,
109.5 degree angles,
4 attached atoms/lone pairs

Front 4

saturated molecule

Back 4

no pi bonds, no rings
2n+ 2 H atoms (n = number of C)

Front 5

degree of unsaturation

Back 5

2n+2-x/2
n= number of carbons,
x=H or (F,Cl,Br,I),
subtract N from x,
ignore O

Front 6

resonance

Back 6

delocalized electrons
delocalization of the electrons stables the molecule due to electrons moving between nonhybridized p-orbitals

Front 7

acidity and s character

Back 7

acidity increases with more s character
sp3 < sp2 < sp

Front 8

acidity and resonance

Back 8

If the conjugate base has resonance, the molecule is more acidic

Front 9

Induction

Back 9

Electronegativity of nearby atoms causes electrons to shift. The shifts occur through sigma bonds

Front 10

Types of reaction intermediates

Back 10

1. Carbocations
2. Alkyl Raidicals
3. Carbanions

Front 11

carbocations

Back 11

reaction intermediate, positively charged species with a full positive charge on carbon.
Will be sp2 hybridized with an empty p orbital

Front 12

carbocation stability

Back 12

tertiary > secondary > primary > methyl

Front 13

alkyl radicals

Back 13

reaction intermediates that contain one unpaired electron, electron deficient. Will be sp2 hybridized with an unpaired electron in an unhybridized p orbital

Front 14

alkyl radical stability

Back 14

tertiary > secondary > primary > methyl

Front 15

carbanions

Back 15

reaction intermediates with a full negative charge on carbon,

Front 16

carbanion stability

Back 16

methyl > primary > secondary > tertiary

Front 17

electron withdrawing groups

Back 17

groups that are more electronegative than carbon pull electron density toward them through sigma bonds. Tend to stabilize electron rich intermediates (carbanions)

Front 18

electron donating groups

Back 18

groups that are less electronegative than carbon tend to donate electrons. Tend to stabilize electron-deficient intermediates (carbocations, radicals). On the MCAT: alkyl substituents.

Front 19

homolytic cleavage

Back 19

one electron of the bond broken goes to each fragment of the molecule creating 2 radicals

Front 20

heterolytic cleavage

Back 20

both electrons go to the same atom forming a cation and anion

Front 21

Isomers

Back 21

different compounds having the same molecular formula

Front 22

Structural/constitutional Isomers

Back 22

Different connectivity (same molecular formula),
different physical and chemical properties

Front 23

Conformational Isomers

Back 23

Different rotation about a sigma bond (same connectivity, same molecular formula),
Same physical and chemical properties,
cannot be isolated,
NEWMAN projections (anti/gauche)

Front 24

Stereoisomers

Back 24

Differ in spatial arrangement (same molecular formula and connectivity)
Two types of stereoisomers: diasteriomers, enantiomers

Front 25

Enantiomers

Back 25

type of stereoisomer (different spatial arrangement),
1. Have at least one chiral center,
2. Each isomer has opposite configuration (R,S),
inversion of every stereocenter in molecule,
3. Each isomer has equal optical rotation but opposite sign (+/-),
5. All other chemical properties are the same

Front 26

Racemic mixture

Back 26

50:50 mixture of enantiomers,
achiral,
no optical activity,
process of separating enantiomers is called resolution

Front 27

Diastereomers

Back 27

type of stereoisomer, nonsuperimposable, non mirror-images,
differ in absolute configuration of at least one (but not all) carbons,
physical and chemical properties can be very different,
specific rotation is different but there is no relationship

Front 28

Epimers

Back 28

Subclass of diastereomers,
inversion of only ONE stereocenter,
all epimers are diastereomers (not all diastereomers are epimers)

Front 29

Absolute configuration

Back 29

R or S assignment of chiral centers

Front 30

Relative configuration

Back 30

D or L assignment based on hydroxyl (-OH) group on the highest numbered chiral center in a Fischer projection.
D: hydroxyl group is on the right,
L: hydroxyl group is on the left

Front 31

Anomers

Back 31

Epimers that form as a result of ring closure.
Only with regards to sugar chemistry,
New stereocenter is formed at anomeric carbon, named alpha (OH group down) or beta (OH group up)

Front 32

Meso compound

Back 32

An internal plane of symmetry in a molecule that contains chiral centers.
Not optically active, type of stereoisomer

Front 33

Geometric Isomer

Back 33

Diastereomers that differ in orientation of substituents around a ring or double bond,
Designated by cis/trans or Z/E

Front 34

Ortho-Para Directors are

Back 34

Activating (except for Halide Deactivators)

* -NH2 (amino)
* -OH (hydroxy)
* NHCOCH3 (acetamide)
* OCOCH3 (acetoxy)
* OR (alkoxy)
* CH3 (methyl)
* C6H5 (phenyl)

Front 35

Meta Directors are

Back 35

Deactivators

* -NO2 (nitro)
* -NR3 (ammonium)
* -CX3 (trihalomethyl)
* -CN (cyano or nitrile)
* -SO3H (sulfonic acid)
* -CHO (aldehyde)
* -COR (ketone)
* -COOH (carboxyl)

Front 36

Ortho-Para Directors

Strong Activators

Back 36

* NH2 (amino)
* -OH (hydroxy)

Front 37

Ortho-Para Directors

Moderate Activators

Back 37

* NHCOCH3 (acetamide)
* OCOCH3 (acetoxy)
* OR (alkoxy)

Front 38

Ortho-Para Directors

Weak Activators

Back 38

* CH3 (methyl)
* C6H5 (phenyl)

Front 39

Ortho-Para directors

Weak Deactivators

Back 39

-I

-Br

-Cl

-F

Front 40

Meta Directors

Strong Deactivators

Back 40

* -NO2 (nitro)
* -NR3 (ammonium)
* -CX3 (trihalomethyl)

Front 41

Meta Directors

Moderate Deactivators

Back 41

* -CN (cyano or nitrile)
* -SO3H (sulfonic acid)
* -CHO (aldehyde)
* -COR (ketone)
* -COOH (carboxyl)

Front 42

An Activating Group

Back 42

Groups which lower the rate of electrophilic substitution. Activators activate the ring, making it more reactive.

Front 43

A Deactivating Group

Back 43

Any substituent that lowers the rate (from benzene) of substitution. Deactivators make the ring less reactive.

Front 44

TLC

Back 44

Separates compounds based on polarity

-Used to separate small amounts of solids or high boiling point liquids

-Uses silica gel

Front 45

TLC

Back 45

Stationary Phase:

Mobile phase: a polar, silica gel plate

-Non-polar migrate faster, high Rf

-Polar, slower, low Rf

Rf (Retention Factor): spot

solvent front

Rf can never be smaller than 1 or negative.

Front 46

Column Choromatography

Back 46

Separates large amounts of solids or high bp liquids.

Separates based on polarity differences.

Mobile phase: a polar, silica gel plate

-Non-polar migrate faster, high Rf

-Polar, slower, low Rf

Rf (Retention Factor): spot

solvent front

Rf can never be smaller than 1 or negative.

Front 47

HPLC

Back 47

Separates based on polarity

Are 2 phases.

Can be done in reverse.

Again: non-polar Mobile phase: a non-polar,

migrate faster

-Polar, slower, low Rf

This flips in Reverse HPLC, with a polar plate and polar molecules traveling more quickly. .

Front 48

Ion Exhange Chrom.

Back 48

Separates compounds based on differences in charge.

Cation-exhange resin: retains cations

Anion-exhange resin: retains anions

-Separates mixtures of charged amino acids, proteins, or nucleotides

Stationary phase: resin containing anionic/cationic groups with counter ions.

Mobile phase: buffered solution

Front 49

Affinity Chrom.

Back 49

Separates biochemical mixtures based on highly specific lock-&-key interactions

Used to separate proteins from blood serum or a cell lysate.

Front 50

Immuno-Affinity hrom.

Back 50

Stationary phase: small particles of resin linked to anti-body-binding proteins

-Magnetic beads may serve as an alternative stationary phase.

Front 51

Metal ion Affinity Chrom

Back 51

Uses recombinant proteins: proteins grafted with a tag at its C or N terminus.

Have a resin that will attract the protein, elute everything else, then elute it out

Front 52

Gas Chrom.

Back 52

Separates based on diffs in volatility or bpt.

-Used to separate small amounts of low bpt compounds.

-Low bpt compounds elute first.

-High bpt compounds elute last.

Volatility is the tendency of a molc to convert to gas.

Front 53

Gas Chromatogram

Back 53

The no. of compounds = the no. of peaks

The relative quantity of each compound from each peak area

The volatility/bpt of the compuonds can be read from the time axis.

Front 54

Distillation

Back 54

Only one phase, seperates based on bpt differences.

Used to separate large amounts of low bpt compounds.

Are a measure of intermolecular forces between liquid molcs.

Front 55

Chromotagraphy

Back 55

Uses 2 phases

Front 56

Bpt and Volatility are:

Back 56

Inversely related to one another.