•  the same general formula
• similar chemical properties - the same functional group
• physical properties that change gradually as their molecular masses               increase

• Alkanes
• Alkenes
• Alkynes

• What is the test for saturation? Write two chemical reactions to explain the test.

Answers:

1. Unsaturated Hydrocarbons are:

• Alkene: Contains at least one carbon-carbon double bond (C=C), making it unsaturated.

• Alkyne: Contains at least one carbon-carbon triple bond (C≡C), making it unsaturated.

2. Classifying Compounds as Organic or Inorganic:

• Paraffine (Paraffin): Organic. Paraffin is a mixture of alkanes (hydrocarbons), typically derived from petroleum, consisting of carbon and hydrogen atoms.

• Baking Soda (Sodium Bicarbonate, NaHCO₃): Inorganic. It contains sodium, hydrogen, carbon, and oxygen but is not primarily carbon-based and lacks the typical structure of organic compounds.

• Lighter Fluid: Organic. Lighter fluid is typically composed of hydrocarbons (e.g., butane or other alkanes), which are carbon-based molecules.

3. Difference in Structure Between Alkanes, Alkenes, and Alkynes:

• Alkanes:

  • General formula: CₙH₂ₙ₊₂

  • Contain only single bonds (C-C) between carbon atoms.

  • Saturated hydrocarbons (no double or triple bonds).

  • Example: Ethane (C₂H₆, H₃C-CH₃).

  • Structure: Linear or branched chains with all single bonds, fully saturated with hydrogen.

• Alkenes:

  • General formula: CₙH₂ₙ

  • Contain at least one double bond (C=C) between carbon atoms.

  • Unsaturated hydrocarbons (fewer hydrogens due to the double bond).

  • Example: Ethene (C₂H₄, H₂C=CH₂).

  • Structure: Contains a planar double bond, which restricts rotation and allows for geometric isomerism (e.g., cis-trans isomers).

• Alkynes:

  • General formula: CₙH₂ₙ₋₂

  • Contain at least one triple bond (C≡C) between carbon atoms.

  • Unsaturated hydrocarbons (even fewer hydrogens than alkenes due to the triple bond).

  • Example: Ethyne (C₂H₂, HC≡CH).

  • Structure: Linear around the triple bond, highly reactive due to the high electron density of the triple bond.

Key Structural Differences:

• Bond Type: Alkanes have single bonds, alkenes have at least one double bond, and alkynes have at least one triple bond.

• Degree of Saturation: Alkanes are saturated (max hydrogen atoms), while alkenes and alkynes are unsaturated (fewer hydrogens due to multiple bonds).

• Reactivity: Alkanes are relatively unreactive due to stable single bonds. Alkenes and alkynes are more reactive because double and triple bonds are electron-rich and prone to addition reactions.

• Geometry: Alkanes are tetrahedral around each carbon, alkenes are planar around the double bond, and alkynes are linear around the triple bond.

  
  

• A homologous series is a group of compounds with the same functional group and the same general formula.
• Examples:
  • Hydrocarbons (Alkanes, alkenes, alkynes)
  • Haloalkanes (also called alkylhalides)
  • Alcohols
  • Carboxylic acids
  • Esters
  • Ketones
  • Aldehydes

• PREFIX
• PARENT (ROOT CHAIN)
• SUFFIX

• The suffix of the name reflects the type(s) of functional group(s) present on the parent chain. 
  • The following suffixes must be used for these functional groups:
    • Alkanes - suffix = "ane"
    • Alkenes - suffix = ene"
    • Alkynes - suffix = "yne"
    • Haloalkanes - The modified name of the halogen is used in the prefix, and is     constructed by dropping the "ine" ending of the halogen's name and adding "o".
      • e.g:
        • fluorine becomes fluoro
          chlorine becomes chloro
          bromine becomes bromo
          iodine becomes iodo
    • Alcohols - suffix = "ol"
    • Carboxylic acid - suffix =  "oic acid"
    • Esters - suffix = "oate"
• Other groups which are attached to the parent chain are called substituted groups of substituents.
• Start numbering the continuous carbon chain closest to the functional group, otherwise closest to a substituted group. (A functional group always "trumps" a substituted group in the numbering of the chain)
• The substituted groups are named in alphabetical order in the naming, together with the numbered carbon they are attached to.
• Prefixes (di, tri, tetra for example) used to designate several groups of the same kind, are not considered when alphabetizing.

• 2-methylpropane and butane are isomers of each other.
• pent-1-ol and pent-3-ol are isomers of each other.
• propanoic acid and metyl ethanoate are isomers of each other. (see below for an example)

• The relative strength of the four intermolecular forces: Ionic > Hydrogen bonding > Dipole-dipole IMFs > London dispersion forces

2.  Number of carbons in chain, Number of electrons in    
     molecule.

• More carbons in the chain, more electrons in molecule. 

• Greater electron cloud density, greater distortion.

• Greater momentary dipoles created within molecule. 

• Momentary dipoles are induced in neighboring molecules. 

• Stronger IMFs - London forces - between molecules. 

• More energy required to overcome the stronger London dispersion IMFs. 

• BP increases with more carbons in the alkane chain.

3.  Branching of the chain

• More branching & more symmetry, weaker IMFs.

• Less energy required to overcome the weaker IMFs

• Lower BP.

• Representation (Molecular, structural, condensed structural formula)
• Homologous series
• Functional groups
• Substituents
• Physical properties (Bonding and intermolecular forces)
• Chemical properties (Reactions)
• IUPAC naming:

1. Naming and drawing of organic compounds is restricted to one type of functional group per compound and to a maximum of two functional groups of the same type per compound, except for haloalkanes, where a maximum of two different halogen substituents (e.g. bromo- and chloro-) are allowed per molecule.
2. The only substituent chains that are allowed in naming and reactions are: methyl- and ethyl- groups.
3. A maximum of THREE substituent chains (alkyl substituents) are allowed on the alkane, alkene, haloalkane, alcohol or carboxylic acid parent chain.
4. When naming haloalkanes, the halogen atoms do not get preference over alkyl groups. 
5. Numbering should start from the end nearest to the first substituent, either the alkyl group or the halogen. In haloalkanes, where e.g. a Br and a Cℓ have the same number when numbered from different ends of the chain, Br gets alphabetical preference.
6. When writing IUPAC names, substituents appear as prefixes written alphabetically (bromo-, chloro-, ethyl-, methyl-), ignoring the prefixes di- and tri-.
7. When writing IUPAC names, the following conventions must be followed:

• Numbers are separated from letters using a dash (−).
• Numbers are separated from numbers using a comma (,).
• Letters are not separated at all (i.e. no space is used), with the exceptions being esters (e.g. methyl ethanoate) and carboxylic acids (e.g. propanoic acid).

1. In some (especially smaller) molecules numbering becomes redundant, but redundancy will not be penalised. For example, methylbut−2−ene may be written as 2−methylbut−2−ene without penalty. The only exception to this is if numbering is always redundant, e.g. for a carboxylic acid: butan−1−oic acid will be penalized, as it must be written as butanoic acid.
2. For phonic purposes, the vowel "e" is generally removed from the name before the suffix, e.g. butan−1−ol instead of butane−1−ol. But this is not done for diols, e.g. butane−1,2−diol is correct, and not butan−1,2−diol.
3. For phonic purposes, the vowel "a" must be added to the name before the suffix for dienes, e.g. buta−1,3−diene is correct, and not but−1,3−diene.

Process of forming chains of connected atoms forming a molecule.

1.2 Homologous series:

a series of compounds which all contain the same functional group, and have similar chemical properties.

1.3 Isomers:

Molecules with the same molecular formula but different structural formula.

1.4 Saturated compound:

Compounds containing the maximum number of hydrogen atoms (no double or triple bonds).