hydrocarbons and alkenes

• organic chemistry is all about compounds that contain carbon
• each atom of carbon can form 4 strong bonds, usually with other carbon atoms or with hydrogen atoms.
• hydrocarbons are any compound formed from carbon and hydrogen only
• alkanes are the simplest hydrocarbons
• Methane has 1 carbon and 4 hydrogens
• Ethane has 2 carbons and 6 hydrogens
• Propane has 3 carbons and 8 hydrogens
• Butane has 4 carbons and 10 hydrogens
• Alkanes are a homologous series because they have similar properties
• the general formula for alkanes is Cn H2n + 2
• Alkanes are saturated compounds meaning every atom has single bonds
• Isomers are molecules that have the same molecular formula, but different structural formulas, this means they are made of the same atoms, but the atoms are arranged differently.

  • For example, the two molecules below both have the formula C5H12 meaning 5 carbon atoms and 12 hydrogen atoms. However, the atoms are arranged differently, which is why they have different names.

  
• Molecules in a homologous series have the same functional group and general formula