Formulae, Functional Groups and Terminology

Summary and Exam Tips for Formulae, Functional Groups and Terminology

Formulae, Functional Groups and Terminology is a subtopic of Organic Chemistry, which falls under the subject Chemistry in the Cambridge IGCSE curriculum. This section focuses on understanding the structure and naming of organic compounds, which are carbon-containing molecules. Key concepts include naming compounds using prefixes like Meth-, Eth-, Prop-, and But- for 1 to 4 carbon atoms, respectively. The suffixes -ane, -ene, -ol, and -oic acid denote functional groups such as alkanes ($C-H/C-C$), alkenes ($C=C$), alcohols ($OH$), and carboxylic acids ($COOH$).

A homologous series is a family of compounds with similar chemical properties due to the same functional group, differing by a $-CH_2-$ unit. For instance, alkanes have the general formula $C_nH_{2n+2}$, while alkenes are $C_nH_{2n}$. Understanding saturated (single carbon-carbon bonds) and unsaturated (one or more double/triple carbon-carbon bonds) compounds is crucial, as it affects their physical state at room temperature.

Structural isomers are compounds with the same molecular formula but different structural arrangements. Recognizing these differences is essential for interpreting molecular and structural formulas, which depict the spatial arrangement of atoms and bonds.

Exam Tips

• Familiarize yourself with the general formulas of each homologous series, such as alkanes ($C_nH_{2n+2}$) and alkenes ($C_nH_{2n}$).
• Remember that saturated compounds have only single bonds, while unsaturated compounds contain double or triple bonds.
• Practice drawing and interpreting displayed formulas to show all atoms and bonds clearly.
• Understand the significance of functional groups in determining the chemical properties of compounds.
• Review past paper questions to get a feel for how these concepts are tested in exams.