Organic Chemistry Exam 1

Chapters 1-4 and partially 5

Formal Charge

present when the number of electrons in bonds and lone pairs about the atom is different from the number of its valence electrons - +1 and -1 are okay but neutral is preferred

Carbon bonding

Usually 4 bonds but can form:

Carbanions - 3 bonds and 2 lone pairs, -1 formal charge

Carbocations - 3 bonds, no lone pairs, formal charge of +!

Radicals - 3 bonds, 1 valence electron, formal charge of 0

reactive intermediates

react quickly and disappear

Nitrogen Bonding

Usually 3 bonds and 1 lone pair but can also form:

4 bonds, formal charge of +1

2 bonds and 2 lone pairs, formal charge of -1

Oxygen Bonding

Usually 2 bonds and 2 lone pairs but can also form:

3 bonds and 1 lone pair, formal charge of +1

1 bond and 3 lone pairs, formal charge of -1

Tetra hydron bonding

109.5 degrees

Kekule structure

structure showing element and bond lines - all elements

condensed structure

Breaking up the structure - CH3CH2CH3 =C3H8

Skeletal

only showing carbons or elements other than H - dont have to put lone pairs

sigma bonds

single bonds

pi bonds

double or triple bonds

valence bond theory

4 electron areas = 4 hybridized orbitals =sp3

electronegativity

an atoms ability to attract shared electrons

Fluorine is most E.N.

E.N. trend goes…

up and right

Bronstead Lowery - Acid

Loses H+ ion

Bronstead-Lowery Base

gains H+ ion

The larger the Ka value the…

stronger the acid

The smaller the pKa value the…

stronger the acid

Stronger acids are borderline…

ionic

The easier it is to break the bond…

the stronger the acid

Between HF and HI, the stronger acid is

HI because it will more easily lose the H+ ion as it is on the most outer orbital with so many layers

The stronger the acid the…(base)

weaker it’s conjugate base

Resonance stabilization

ions with multiple resonance structures are more stable than ones with only one

share the burden of a charge

Inductive Effect

very electronegative atoms pull electron density from distances of more than one bond - ONLY TIE BREAKER

the tie breaker for determining most acidic is…

inductive effect

Hybridization

The more % s orbitals to hold the negative charge the more stable an ion

sp more acidic than sp3

on structures, a lone pair means an atom is…

basic

an COOH or bonded H on atom means an atom is…

acidic

cations are (basic or acidic)

acidic

Hydrocarbons

only H and C in compounds - commonly fuels

saturated

all carbons are SP3 hybridized single bonds

unsaturated

pi bonds on carbon - missing hydrogens

Alkanes are also called

Aliphatic hydrocarbons

Alkanes

straight carbon chain with no pi bonds - saturated

Alkenes

hydrocarbons that contain double bond

Alkynes

hydrocarbons with a triple bond

Alcohols

OH on a molecule (ROH)

Ethers

a bridging oxygen (ROR)

Amines

Nitrogen with single bonds (RNH2, R2NH, R3N)

Aldehydes

C double bonded to O and single bonded to H (RCHO) - ALWAYS ON THE END

Ketones

CO - C double bonded to O and bridging an ion (R2CO)

Carboxylic Acids

very acidic (RCOOH) or (RCO2H) C double bonded to O and single bonded to O - same O single bonded to H

Ester

(RCOOR) or (RCO2R) same as carboxylic acid but O is bonded to molecule, not H

Amides

(RCONHR) or (RCONR2) a C double bonded to O and single bonded to N

Classification on Hydrogen and Carbon atoms bonding to Carbon

primary (1 degree) - bonded to one C

secondary (2 degree) -bonded to two C

Tertiary (3 degree) - bonded to three C

Quaternary (4 degree) - bonded to four C

Naming steps

1) parent branch - longest chain of C

2) count until hit branch - if branches are on same count cc or cw go alphabetically

3)categorize branches

4)add prefixes based on how frequent branch occurs

5)ignore prefixes and alphabetize

6)put all together

methyl ethyl also means

isopropyl - looks like a Y branch

In naming, () are used when

a branch is on a branch

Tert-butyl

snowman hand - carbon branch bonded to three CH3

Sec-butyl

A carbon branch with Y^

Newman projection

a single bond shown in multiple arrangements

cyclo

a ring structure in front of the alkane root

If you hit branches on the same numbers going clockwise and counterclockwise you should…

go alphabetical

Iodine branch name…

iodo

more energy is in bonds without

the correct angles

axial bonds

are up and down

equatorial bonds

go opposite of the axial bond

a ring flip change

switches equatorial to axial and vice versa

large groups want to be…

equatorial, more space to move

cis

both up or down

trans

alternating up and down

t or f it matters if a branch is axial or equatorial to be cis or trans?

FALSE