Overview
This lecture introduces hydrocarbons, focusing on alkanes, their definitions, structures, formulas, and key characteristics in organic chemistry.
Introduction to Organic Chemistry
- Organic chemistry studies compounds containing carbon.
- Carbon atoms form four strong bonds, often with hydrogen or other carbons.
Hydrocarbons
- Hydrocarbons are compounds containing only carbon and hydrogen atoms.
- Example: Butane (C₄H₁₀) is a hydrocarbon; butanol is not, since it contains oxygen.
Alkanes: Structure and Examples
- Alkanes are the simplest type of hydrocarbons.
- The first four alkanes: methane (CH₄), ethane (C₂H₆), propane (C₃H₈), butane (C₄H₁₀).
- Each successive alkane increases by one carbon and two hydrogens.
Homologous Series and General Formula
- Alkanes are part of a homologous series—organic compounds with similar properties and reactions.
- The general formula for alkanes is CₙH₂ₙ₊₂ (n = number of carbons).
- Example: Propane (n=3) fits the formula: C₃H₈; Octane (n=8) is C₈H₁₈.
Saturation of Alkanes
- Alkanes are saturated compounds—every carbon atom forms four single covalent bonds.
- No carbon-carbon double bonds are present in alkanes.
- If a double bond is added, the compound becomes an alkene, not an alkane.
Key Terms & Definitions
- Organic chemistry — the study of carbon-containing compounds.
- Hydrocarbon — a molecule made only of carbon and hydrogen atoms.
- Alkane — a saturated hydrocarbon with only single bonds (CₙH₂ₙ₊₂).
- Homologous series — a family of compounds with similar properties and structure.
- Saturated compound — a compound where each carbon forms four single covalent bonds.
- Alkene — an unsaturated hydrocarbon with at least one double bond between carbon atoms.
Action Items / Next Steps
- Review the first four alkanes and memorize their formulas.
- Practice using the alkane general formula (CₙH₂ₙ₊₂) to calculate molecular formulas.
- Prepare for the next lesson on properties of alkanes and combustion equations.