topic 10.1: fundamentals of organic chemistry notes · organic chemistry notes. terminology...

Topic 10.1: Fundamentals of

Organic Chemistry Notes

TerminologyHydrocarbon: compounds that contain mostly hydrogen and carbon

Homologous Series: compounds with the same general formula

Molecular Formula: shows the number of atoms only (C2H6O)

Structural Formula: shows how the atoms are arranged

Condensed: CH3CH2OH

Empirical Formula: shows lowest whole number ratio of atoms

Examples: Homologous Series = CnH(2n+2)

Molecular Formula = C4H10

Structural formula:

Condensed S.F. = CH3CH2CH2CH3

Empirical Formula = C2H5

Homologous Series

The general trend for all molecules in a homologous series is an increase in the boiling point. This is because of the effect of London Dispersion Forces and the molecular weights of the lengthening carbon chains

Structural IsomersStructural Isomer: same molecular formula but different structure

Straight Chain- C4H10

CH3CH2CH2CH3Branched Chain- C4H10

CH3CH2(CH2)CH3

Functional GroupsDefinition: Atoms or groups of atoms attached to a hydrocarbon

They are usually the reactive groups on a stable carbon chain so form the important part of the molecules

Examples:

● Alcohols● Aldehydes● Ketones● Carboxylic Acids● Halides (Halogenoalkanes)

Class Name AlkanesFormula CnH2n+2

Functional Group Name

alkyl

Functional Group noneSuffix -ane

Alkyl GroupsBranches on carbon chains

-CH3 methyl

-CH2CH3 ethyl

IUPAC Naming Summary

1. Count the C’s in the longest chain 2. Name each attached group3. Count the longest carbon chain to give

the first attached group the smallest number

4. Name and locate each group

Naming Branched Alkanes

Class Name AlkeneFormula CnH2n

Functional Group Name

alkenyl

Functional Group

Suffix -ene

AlkenesName Number of

CarbonsCondensed Structural Formula

Ethene 2 CH2CH2

Propene 3 CH2CHCH3

Butene 4 CH2CHCH2CH3

Pentene 5 CH2CHCH2CH2CH3

Hexene 6 CH2CHCH2CH2CH2CH3

Naming Branched Alkenes 1. Select the longest chain of C atoms containing the double bond and

number the chain from this end2. Place the ending -ene on the basic name3. Use a number to indicate the lower number carbon of the C=C bond4. As in alkanes, prefix with substituents5. Side chain positions are based on the number allocated to the first C

of the C=C

CH3- CH = CH - CH2- CH(CH3) - CH3

5-methylhex-2-ene

Structural Isomerism of AlkenesDifferent structures are possible due to….different positions

for the double bond

Alkynes- very unstableName Number of

CarbonsCondensed Structural Formula

Ethyne 2 CHCH

Propyne 3 CHCCH3

Butyne 4 CHCCH2CH3

Pentyne 5 CHCCH2CH2CH3

Hexyne 6 CHCCH2CH2CH2CH3

Class Name AlkyneFormula CnH2n-2

Functional Group Name

alkynyl

Functional Group

Suffix -yne

Saturated vs. Unsaturated

Saturated Hydrocarbons are hydrocarbons that contain no double or triple bonds (alkanes)

- They are saturated with hydrogens

Unsaturated hydrocarbons are alkenes and alkynes

Class Name Halogenoalkane

Formula CnH2n+1X

Functional Group Name

X= F, Cl, Br, or I

Functional Group

Suffix nonePrefix Fluoro-, chloro-, bromo-, iodo

Halides and NamingDifferent positions for the halogen and branching of the carbon chain

1-chlorobutane 2-chlorobutane

1- chloro-2-methylpropane2- chloro-2-methylpropane

HalidesThe number of carbons that are joined to the carbon with the halogen group determine if it is a 1°, 2°, or 3° halide.

Tertiary 3°

Will react differently due to shielding effects from the other carbons

Class Name Alcohols

Formula R-OH

Functional Group Name

Hydroxyl

Functional Group

Suffix -ol

Naming AlcoholsFull Structural Formula Skeletal Structure Name

Ethanol

Propan-1-ol

Propan-2-ol

Full Structural Formula Skeletal Structure Name

Pentan-3-ol

AlcoholsThe number of carbons that are joined to the carbon with the alcohol group determine if it is a 1°, 2°, or 3° alcohol.

Class Name Ether

Formula ROR’

Functional Group Name

Ether

Functional Group

Suffix nonePrefix -oxy-

Naming Ethers

Methoxy methane

2-ethoxy-2-methylpropane

Class Name Aldehyde

Formula RCHO

Functional Group Name

Aldehyde

Functional Group

Suffix -al

Naming AldehydesName Condensed Structural Formula

Ethanal CH3CHO

Propanal CH3CH2CHO

Butanal CH3CH2CH2CHO

Pentanal CH3CH2CH2CH2CHO

Class Name Ketone

Formula RC(O)R’

Functional Group Name

Carbonyl

Functional Group

Suffix -one

Naming KetonesName Condensed Structural Formula

Propanone CH3COCH3

Butanone CH3CH2COCH3

Pentan-2-one CH3COCH2CH2CH3

Pentan-3-one CH3CH2COCH2CH3

Class Name Ester

Formula RCOOR’

Functional Group Name

Ester

Functional Group

Suffix -oate

Naming Esters1. Always take the carbon chain with the double bond as the

initial stem. The side group is next to the single bonded oxygen.

2. Add -oate

Methyl ethanoate Ethyl methanoate

Class Name Carboxylic Acid

Formula RCOOH

Functional Group Name

Carboxyl

Functional Group

Suffix -oic acid

Carboxylic AcidsCarboxylic Acids form a homologous series

Naming Carboxylic Acids1. Select the longest chain of C atoms containing the COOH group2. Remove the e and add oic acid after the basic name3. Number the chain starting from the end nearer the COOH group4. As in alkanes, prefix with alkyl substituents5. Side chain positions are based on the C in COOH being 1

CH3- CH(CH3) - CH2 - CH2 - COOH

4-methylpentanoic acid

Class Name Amine

Formula RNH2 (H=R)

Functional Group Name

amino

Functional Group

Suffix -amine

Happy News!!IB expects you to be familiar with the nitrogen containing functional groups

(amines, amides, nitriles) but nomenclature of these classes of compounds will not be assessed

Naming AminesNomenclature: Named after the groups surrounding the nitrogen + amine

Name Condensed Structural Formula

Ethylamine C2H5NH2

dimethyamine (CH3)2NH

trimethylamine (CH3)3N

Class Name Amide

Formula RCONH2

Functional Group Name

carboxamide

Functional Group

Suffix -amide

Naming Amides● Solids named from the corresponding acid● Remove oic acid, add amide

CH3CONH2 ethanamide

C2H5CONHC6H5 N- phenyl propanamide

● The N tells you the substituent is on the nitrogen

Class Name Nitrile

Formula RCN

Functional Group Name

cyano

Functional Group

Suffix -nitrile

Naming NitrilesButanenitrile

CH3CH2CH2C☰N

Ethanenitrile

CH3C☰N

Class Name areneFormula CnH2n-6

Functional Group Name

phenyl

Functional Group

Suffix none

Benzene

Due to the resonance energy or stabilization energy of benzene, it is reluctant to undergo addition reactions, but will undergo substitution reactions.

Delocalization minimizes the repulsion between electrons

Physical Evidence for Benzene StabilityX-Ray Bond Length Data (nm):

Alkane Single Bond C-C 0.154 nm

Alkene Double Bond C=C 0.134 nm

Benzene 0.139nm

Naming ArenesArenes are compounds with a benzene ring. Aliphatics on the other hand are compounds without a benzene ring such as alkanes and alkenes.

Bromobenzene

1,2- diphenylethyne

Physical Characteristics of the Functional Groups● Explain volatility between functional groups

○ H Bonding and Van der Waals (Dipole-Dipole and London Dispersion Forces)

● Explain Solubility- Need to be polar and smallEthanal CH2CHO (BP) 21 Soluble

Propanal C2H5CHO (BP) 46 Slightly Soluble

Effects of lengthening chain and branching