DAT Organic Chemistry - Mike's Videos

2 electron domains: geometry, bond angle, hybridization

Linear

180

sp

3 electron domains: geometry, bond angle, hybridization

Trigonal planar

120

sp2

4 electron domains: geometry, bond angle, hybridization

Tetrahedral

109.5

sp3

Condensed formula

Can be written in a single line of print

# of bonds: single bond

one sigma

# of bonds: double bond

one sigma + one pi

# of bonds: triple bond

one sigma + two pi

Pi bonds are formed by which orbitals?

2 p-orbitals

How would one best describe the orbital required to form a σ bond? Select all that apply.

I. Overlap of two s-orbitals

II. Overlap of one s- and one p-orbital

III. Overlap of two p-orbitals

IV. Parallel overlap of two p-orbitals

I, II, III

For resonance structures, only ________________ move

Electrons (pi electrons, lone-pair electrons, or negative charges)

For resonance structures, you can move electrons toward/into an atom that _____________________

Does not have a full octet

If an atom already has a full octet, then you can move electrons into it only if _____________________

You push electrons out the opposite side

For resonance structures, do not move or break _________________

Sigma bonds

Major resonance contributor rules

Most stable resonance structure will have:

1. A full octet on every atom

2. The smallest possible number of charges

3. Negative charges on the most EN atoms and positive charges on the least EN atoms

Allyl carbocation

Carbocation that is one position away from a double bond

Allyl carbanion

Carbanion that is one position away from a double bond

Order of stability in Newman Projections from most to least

Staggered > Gauche > Eclipsed

Gauche interaction

Occur whenever 2 substituents larger than hydrogen are adjacent to each other in a staggered conformation

Most stable cycloalkane

Cyclohexane

Which is more stable: axial or equatorial? Why

Equatorial

1, 3-diaxial interactions

How to achieve the greatest stability in cyclohexane rings

Placing the largest substituents in the equatorial positions

Trans vs. cis cyclohexanes

Trans: 2 substituents going in opposite directions

Cis: 2 substituents going in same direction

Bronsted acid

Substance that donates H+ ions (protons)

Bronsted base

Substance that accepts H+ ions

Lewis acid

Substance that accepts electrons

Lewsi base

Substance that donates electrons

Conjugate acid =

Base + an H + 1 charge

The stronger/more reactive the acid, the _________________ its conjugate base

Weaker/more stable

The stronger/more reactive the base, the _________________ its conjugate acid

Weaker/more stable

Increase Ka = ________________ pKa = ________________ acid strength

Decrease

Increase

pKa of H2O

16

pKa of H3O+

-2

pKa of H3CCOOH

5

pKa of NH4+

10

pKa of H3CCOCH3

20

pKa of C6H5OH

10

Increase Kb = _________________ pKb = _________________ base strength

Decrease

Increase

Mnemonic for ranking acids and bases

Charge

Atom

Resonance

Dipole Induction

Orbital hybridization

The more positively-charged a compound is = the more ________________

Acidic

The more negatively-charged a compound is = the more ________________

Basic

H's acidity increases as the atom that it's bonded to

1. Goes left to right across a row on the periodic table (increasing EN)

2. Goes down a column on the PT (increasing size)

A resonance-stabilized conjugate base will be a _______________ acid

Stronger

Electron withdrawing groups ________________ acidity

Increase

Electron donating groups ________________ acidity

Decrease

Electron-withdrawing appendages (not involving aromatic rings) include

EN atoms or groups (F, Cl, Br, I, N, or O)

Electron donors (not involving aromatic rings) are generally

H or C groups

Electron withdrawers (bonded to aromatic rings) include

Halogen atoms

Groups with double/triple bonds

Electron donors (bonded to aromatic rings)

An atom with at least one lone pair e-

Atoms bonded by single bonds

An alkyl or aryl group

Withdrawing groups __________________ basicity because ___________________

Decrease

They make basic electrons less available

Donating groups __________________ basicity because ____________________

Increase

They make basic electrons more available

S-orbitals tend to be _____________ EN than P-orbitals

More

The more "s-character" an atom has, the ________________ the acid

Stronger

Order the following from least to most acidic: sp3, sp2, sp

sp3 < sp2 < sp

IUPAC names for simple hydrocarbon parent chains 1-10

Methane

Ethane

Propane

Butane

Pentane

Hexane

Heptane

Octane

Nonane

Decane

Isopropyl

Sec-butyl

Isobutyl

tert-butyl

Phenyl

Benzyl

Steps for naming alkanes

1. Find parent chain (longest C chain) with the smallest substituent number at the first point of difference

2. Count number of C atoms in the parent chain

3. Identify and number the substituents

4. Write name as a single word with substituents in order

-Substituents (replace "ane" with "yl") + parent chain

When there are 2 substituents on a cyclic molecule, direction is indicated by

Cis: same side

Trans: opposite side

If there are more than 2 substituents, their direction is indicated by

Stereochemical configurations (R/S)

Is the cyclic portion of an alkane the parent chain or the noncyclic portion?

Cyclic

Naming alkyl halides

Can follow the same rules for naming alkanes, using prefixes "fluoro-", "bromo-", "chloro-", "iodo-"

OR can use suffixes "-yl fluoride", etc.

Naming alkenes

1. Use suffix "-ene"

2. Number the double bound (LOWEST possible)

3. Add prefixes "cis" or "trans" if there is one H on each of the 2 alkene C=C carbons

OR

3. Use E/Z naming system (E: opposite sides, Z: same sides)

Determining priority for alkenes

1. Highest atomic number = highest priority

2. If there is a tie, move to adjacent carbons until the tie is broken

3. Multiple-bonded atoms are counted as the same number of single-bonded atoms

Naming alkynes

1. Use suffix "yne"

2. Add number at the start of the triple bond

NO cis/trans E/Z because the bond is linear

Naming alcohols

1. Parent chain is the longest chain with the hydroxyl group

2. Give the smallest number to the C bonded to the hydroxyl group (higher priority than cycloalkanes, amines, alkenes, ethers, and alkyl halides)

4. Change suffix "-e" to "-ol"

Naming ethers

1. Name the 2 alkyl groups as substituents with "ether" at the end

OR

2. Consider the longest carbon chain to be the parent chain and the alkoxy group to be a substituent

Naming primary amines

Add suffix "amine" to the name of the organic substituent

Naming symmetrical and secondary amines

Add "di-" or "tri-" to the alkyl group

Naming asymmetrical amines

Name as N-substituted primary amines, with the largest alkyl group as the parent chain

Naming aldehydes

1. Number parent chain in direction that gives highest priority to the aldehyde carbon

2. Replace "-e" with "-al"

Naming ketones

1. Name parent chain with priority given to the ketone carbon

2. Replace "-e" with "-one"

3. Carbonyl carbon in a cyclic ketone is assumed to be the #1 carbon

Naming carboxylic acids

1. Number parent chain with the carboxylic group at #1 C

2. Replace "-ane" for "-oic acid"

Naming acid halids

1. Number parent chain with the acid halide at #1 C

2. Replace "-ane" for "-oyl halide"

Naming esters

1. Alkyl group attached to the ester oxygen is listed first with the suffix "-yl"

2. Parent chain follows and the suffix is replaced with "-oate"

Naming amides

1. Name alkyl groups attached to the N as "N-methyl/ethyl/etc."

2. Parent chain starts at the carbonyl carbon and is counted moving away from the amide

Naming acid anhydrides

1. Determine length of the chain on either side of the bridging oxygen

2. List both lengths alphabetically, replacing suffix "-e" with "-oic"

3. Write "anhydride" at the end

Naming nitriles

1. Parent chain is the longest C chain that involves the nitrile C

2. Number parent chain in direction that gives the smallest number (always 1) to the nitrile C

3. Add the suffix "nitrile" to the parent name

Bromobenzene

Chlorobenzene

Nitrobenzene

Ethylbenzene

Toulene

Phenol

Aniline

Benzenesulfonic acid

Anisole

Styrene

Benzaldehyde

Benzoic acid

Benzonitrile

Naming substituted benzenes

1. Identify the parent chain with the highest-priority functional group

2. C atom that is attached to the priority functional group is #1

3. Number around the ring clockwise/counter-clockwise to obtain the lowest number at the first point of difference

Naming spiro alkanes

1. Count TOTAL number of carbons across the entire molecule (parent name)

2. Count number of carbons to the left + right of the spiro-carbon center (a and b, from lowest to highest)

3. Write the final name as spiro[a.b]parent name

Naming bicyclic alkanes

1. Count TOTAL number of carbons across the entire molecule (parent number)

2. Count number of carbons to the left/right/above the bridgehead carbons (written as a, b, and c from highest to lowest)

3. Write final name as bicyclo[a.b.c]parentname

Spiro vs. bicyclic alkane

Spiro: fused at a single C atom

Bicyclic: fused across a bridge

Enantiomers

Same chemical formula, same bonding connections

Non-superimposable mirror-image molecules

Diastereomers

Same chemical formula, same bonding connections

NOT non-superimposable mirror-image molecules