IGCSE Chemistry: Organic Chemistry Demystified

Organic chemistry is an essential branch of chemistry that focuses on the study of carbon compounds and their reactions. In IGCSE Chemistry, understanding organic chemistry is crucial, as it covers a wide range of topics, from hydrocarbons to functional groups to polymerization. Here's a guide to demystify organic chemistry:

 1. Understanding Carbon Compounds:

- Unique Properties: Carbon forms the basis of organic chemistry due to its ability to form stable bonds with a wide range of other elements, including itself. This ability to form stable bonds gives carbon compounds their unique properties.

- Functional Groups: Organic compounds often contain functional groups, which are specific arrangements of atoms within a molecule that determine its chemical properties. Common functional groups include alcohols, carboxylic acids, and esters.

 2. Hydrocarbons and Their Properties:

- Alkanes: Alkanes are saturated hydrocarbons that contain only single bonds between carbon atoms. They are relatively unreactive but can undergo combustion reactions to produce carbon dioxide and water.

- Alkenes and Alkynes: Alkenes and alkynes are unsaturated hydrocarbons that contain double and triple bonds, respectively. They are more reactive than alkanes and can undergo addition reactions.

 3. Nomenclature of Organic Compounds:

- IUPAC Rules: The International Union of Pure and Applied Chemistry (IUPAC) has established a set of rules for naming organic compounds. These rules are based on the number and arrangement of carbon atoms and the functional groups present in the molecule.

- Naming Alkanes: Alkanes are named based on the number of carbon atoms in the longest continuous chain, with the suffix "-ane" indicating that the compound contains only single bonds.

 4. Isomerism in Organic Chemistry:

- Structural Isomers: Structural isomers have the same molecular formula but different structural arrangements. They can differ in the order of attachment of atoms or in the orientation of functional groups.

- Geometric Isomers: Geometric isomers have the same molecular formula and the same structural arrangement but differ in the spatial arrangement of atoms due to restricted rotation around a double bond.

 5. Functional Groups and Their Reactions:

- Alcohols: Alcohols contain the hydroxyl functional group (-OH). They can undergo oxidation to form carboxylic acids or esters, and they can also undergo dehydration to form alkenes.

- Carboxylic Acids: Carboxylic acids contain the carboxyl functional group (-COOH). They can undergo esterification to form esters or decarboxylation to form alkanes.

 6. Polymerization:

- Addition Polymerization: In addition polymerization, monomers are added to a growing polymer chain. This process is used to produce polymers like polyethylene and polypropylene.

- Condensation Polymerization: In condensation polymerization, monomers combine to form a polymer, with the elimination of a small molecule like water or hydrogen chloride. This process is used to produce polymers like nylon and polyester.


Organic chemistry is a fascinating and important branch of chemistry that plays a crucial role in IGCSE Chemistry. By understanding the unique properties of carbon compounds, the nomenclature of organic compounds, and the various types of isomerism, you can demystify organic chemistry and excel in your studies. Remember to practice naming compounds and identifying functional groups to reinforce your understanding of the material.