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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