Organic Chemsistry Flashcards
Functional group
A specific atom/group of atoms that determines the chemical properties and reactions of a molecule.
Homologous series
A series of organic compounds with the same functional group and general formula, differing by CH₂ units.
Nomenclature Rules (IUPAC):
- Identify the longest carbon chain.
- Number the chain giving substituents the lowest possible numbers.
- Name and order substituents alphabetically with position numbers.
Types of Organic Compounds:
Alkanes – CₙH₂ₙ₊₂, saturated. hydrocarbons.
Alkenes – CₙH₂ₙ, contain C=C double bond.
Haloalkanes – contain halogen atoms.
Alcohols – contain –OH group.
Aldehydes – contain terminal –CHO group.
Ketones – contain internal C=O group.
Carboxylic acids – contain –COOH group.
Esters, Amines, Amides appear in A2 content.
Structural isomers
same molecular formula, different structural arrangement.
Eg Chain isomers
• Position isomers
• Functional group isomers
Stereoisomers
• E/Z (Geometrical) Isomerism: due to restricted rotation around C=C. Use CIP rules to assign priorities.
Optical Isomerism (A2):
chiral centres produce enantiomers.
Alkanes
- are active due to strong sigma bonds. —-Combustion:
• Complete: produces CO₂ and H₂O.
• Incomplete: produces CO and/or C (soot), dangerous in enclosed spaces.
• Free Radical Substitution (e.g. Chlorination):
• Requires UV light.
• Initiation: Cl₂ → 2Cl•
• Propagation: Cl• + CH₄ → HCl + CH₃•, CH₃• + Cl₂ → CH₃Cl + Cl•
• Termination: 2Cl• → Cl₂, CH₃• + Cl• → CH₃Cl, CH₃• + CH₃• → C₂H₆
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Alkenes
• Electrophilic Addition Reactions:
• π bond is electron-rich → attacks electrophiles.
• Reactions: with HBr, H₂ (Ni catalyst), Br₂ (test for unsaturation), steam (H₃PO₄ catalyst).
• Mechanism Example: Ethene + HBr
1. Electrophile (Hδ⁺) attracted to π electrons.
2. Carbocation intermediate formed.
3. Nucleophile (Br⁻) attacks carbocation.
• Markovnikov’s Rule: more stable carbocation intermediate forms preferentially.
• Addition Polymerisation: Monomers join to form polymers like poly(ethene).
