Organic Chemistry: Alkanes

Alkanes

• Definition: Saturated hydrocarbons with single bonds between carbon atoms
• General formula: CnH2n+2
• Properties:
  • Non-polar and non-reactive
  • Low boiling points and melting points
  • Insoluble in water, but soluble in non-polar solvents
• Naming:
  • Use the prefix "n-" for straight-chain alkanes
  • Use the prefix "iso-" for branched alkanes
  • Use the prefix "neo-" for highly branched alkanes
• Examples: methane (CH4), ethane (C2H6), propane (C3H8)

Alkenes

• Definition: Unsaturated hydrocarbons with one or more carbon-carbon double bonds
• General formula: CnH2n
• Properties:
  • More reactive than alkanes due to the double bond
  • Higher boiling points and melting points than alkanes
  • Soluble in non-polar solvents, but less soluble in water
• Naming:
  • Use the suffix "-ene" to indicate the presence of a double bond
  • Use the prefix "cis-" or "trans-" to indicate the stereochemistry of the double bond
• Examples: ethene (C2H4), propene (C3H6), butene (C4H8)

Alkynes

• Definition: Unsaturated hydrocarbons with one or more carbon-carbon triple bonds
• General formula: CnH2n-2
• Properties:
  • More reactive than alkenes due to the triple bond
  • Higher boiling points and melting points than alkenes
  • Soluble in non-polar solvents, but less soluble in water
• Naming:
  • Use the suffix "-yne" to indicate the presence of a triple bond
  • Use the prefix "cis-" or "trans-" to indicate the stereochemistry of the triple bond
• Examples: ethyne (C2H2), propyne (C3H4), butyne (C4H6)

Isomers

• Definition: Molecules with the same molecular formula, but different structures
• Types:
  • Structural isomers: different bond connections between atoms
  • Stereoisomers: same bond connections, but different 3D arrangements
  • Enantiomers: non-superimposable mirror images
• Examples:
  • Butane (C4H10) has two structural isomers: n-butane and isobutane
  • 2-butene (C4H8) has two stereoisomers: cis-2-butene and trans-2-butene

Alkanes

• Saturated hydrocarbons with single bonds between carbon atoms
• General formula: CnH2n+2
• Non-polar and non-reactive, resulting in low boiling points and melting points
• Insoluble in water, but soluble in non-polar solvents
• Naming conventions include "n-" for straight-chain, "iso-" for branched, and "neo-" for highly branched alkanes
• Examples include methane (CH4), ethane (C2H6), and propane (C3H8)

Alkenes

• Unsaturated hydrocarbons with one or more carbon-carbon double bonds
• General formula: CnH2n
• More reactive than alkanes due to the double bond
• Higher boiling points and melting points than alkanes
• Soluble in non-polar solvents, but less soluble in water
• Naming conventions include using the suffix "-ene" and prefixes "cis-" or "trans-" to indicate stereochemistry
• Examples include ethene (C2H4), propene (C3H6), and butene (C4H8)

Alkynes

• Unsaturated hydrocarbons with one or more carbon-carbon triple bonds
• General formula: CnH2n-2
• More reactive than alkenes due to the triple bond
• Higher boiling points and melting points than alkenes
• Soluble in non-polar solvents, but less soluble in water
• Naming conventions include using the suffix "-yne" and prefixes "cis-" or "trans-" to indicate stereochemistry
• Examples include ethyne (C2H2), propyne (C3H4), and butyne (C4H6)

Isomers

• Molecules with the same molecular formula, but different structures
• Types of isomers include structural isomers, stereoisomers, and enantiomers
• Structural isomers have different bond connections between atoms
• Stereoisomers have the same bond connections, but different 3D arrangements
• Enantiomers are non-superimposable mirror images
• Examples of isomers include butane (C4H10) with two structural isomers, and 2-butene (C4H8) with two stereoisomers

Hydrocarbons

• Alkanes:
  • Definition: Saturated hydrocarbons with single bonds between carbon atoms
  • General Formula: CnH2n+2
  • Non-polar and hydrophobic, insoluble in water, and soluble in non-polar solvents
  • Boiling point and melting point increase with molecular weight
  • Examples: Methane (CH4), Ethane (C2H6), Propane (C3H8)
  • Nomenclature: Use prefixes (meth-, eth-, prop-) and suffix (-ane) to name alkanes

Alkenes

• Definition: Unsaturated hydrocarbons with one or more carbon-carbon double bonds
• General Formula: CnH2n
• Properties:
  • Polar and slightly hydrophilic
  • Soluble in non-polar solvents and slightly soluble in water
  • Reactivity increases with the number of double bonds
• Examples: Ethene (C2H4), Propene (C3H6), Butene (C4H8)
• Nomenclature: Use prefixes (eth-, prop-, but-) and suffix (-ene) to name alkenes
• Stereochemistry: Alkenes exhibit cis-trans isomerism

Alkynes

• Definition: Unsaturated hydrocarbons with one or more carbon-carbon triple bonds
• General Formula: CnH2n-2
• Properties:
  • Highly reactive and polar
  • Soluble in non-polar solvents and insoluble in water
  • Reactivity increases with the number of triple bonds
• Examples: Ethyne (C2H2), Propyne (C3H4), Butyne (C4H6)
• Nomenclature: Use prefixes (eth-, prop-, but-) and suffix (-yne) to name alkynes

Alkanes

• General formula is CnH2n+2, with single bonds between carbon atoms
• Examples include methane (CH4), ethane (C2H6), and propane (C3H8)
• Physical properties include:
  • Low boiling points
  • Low melting points
  • Insolubility in water
  • Solubility in non-polar solvents
• Chemical properties include:
  • Unreactivity due to strong C-H and C-C bonds
  • Combustion reactions with oxygen
  • Substitution reactions with halogens

Alkynes

• General formula is CnH2n-2, with triple bonds between carbon atoms
• Examples include ethyne (C2H2) and propyne (C3H4)
• Physical properties include:
  • Higher boiling points and melting points compared to alkanes
  • Solubility in non-polar solvents
  • Acidic properties
• Chemical properties include:
  • High reactivity due to high energy triple bonds
  • Addition reactions with hydrogen, halogens, and other molecules
  • Polymerization reactions

Alkenes

• General formula is CnH2n, with double bonds between carbon atoms
• Examples include ethene (C2H4) and propene (C3H6)
• Physical properties include:
  • Higher boiling points and melting points compared to alkanes
  • Solubility in non-polar solvents
• Chemical properties include:
  • Reactivity due to high energy double bonds
  • Addition reactions with hydrogen, halogens, and other molecules
  • Polymerization reactions
  • Geometric isomerism (cis-trans isomerism) due to restricted rotation around the double bond