Introduction to Organic Chemistry

What is Organic Chemistry?

• Organic chemistry is the study of the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. Example: CH4, CH3COOH etc.

• Some common bonding patterns that you will encounter in introductory organic chemistry:
• Carbon can have four single bonds, or one double bond and two single bonds, or two double bonds, or one triple bond and a single bond Example:

• Hydrogen can have one bond only and can never be the central atom Example:

• Oxygen can have two single bonds or one double bond Example:

• Nitrogen can have three single bonds, or one double bond and one single bond or one triple bond Example:

Introduction to Hydrocarbons

• A hydrocarbon is an organic compound that only contains carbon and hydrogen atoms
• Simplest organic molecules
• Non-polar
• Small hydrocarbons are often used as fuels in combustion reactions and as solvents

• Aliphatic hydrocarbons: compounds that have a structure based on straight or branched chains or rings of carbon atoms

• Aromatic hydrocarbons: a compound with a structure based on benzene (C6H6).

Unsaturated vs Saturated Hydrocarbons

• A saturated hydrocarbon is one that has the maximum number of hydrogens added
• There are no double or triple bonds. Alkanes are saturated hydrocarbons
• Alkenes and alkynes are unsaturated hydrocarbons

• Alkanes are hydrocarbons that only have single bonds between carbon atoms General molecular formula: CnH2n+2
• Alkenes are hydrocarbons that have at least 1 C=C double bond General molecular formula: CnH2n
• Alkynes are hydrocarbons that contain at least 1 C≡C triple bond General molecular formula: CnH2n-2

Isomers

• If two hydrocarbons have the same number of atoms but different bond connectivity then they are structural isomers.

• Both molecules above have a molecular formula of C5H12 but have very different structures.

Ways to Represent Hydrocarbons