4.1 Organic Chemistry Introduction

REVISION NOTES

IGCSE Edexcel Chemistry

4.1 Introduction

4.1.1 Know that a hydrocarbon is a compound of hydrogen and carbon only

Hydrocarbon is a compound containing hydrogen and carbon only.

4.1.2 Understand how to represent organic molecules using empirical formulae, molecular formulae, general formulae, structural formulae and displayed formulae

Empirical formula shows the simplest whole number ratio of atoms
Molecular formula shows the actual number of atoms
General formula shows a ratio of atoms in a family of compounds in terms of ‘n’ where n is a varying whole number
Simplified Structural formula shows the way in which atoms are bonded (Structure), but not all bonds
Displayed Structural formula shows all atoms and bonds in a molecule

4.1.3 Know what is meant by the terms homologous series, functional group and isomerism

HOMOLOGOUS SERIES

Series of compounds with:
- Same functional group
- Same general formula
- Similar chemical properties
- Gradually increasing physical properties along the series (e.g. boiling point)

FUNCTIONAL GROUP

A group of atoms present in the compound
It is a distinctive combination of atoms in the compound
It is responsible for the chemical reactions of a compound

ISOMERISM

Compounds with:
- Same molecular formula
- But different structural formula
- Due to different arrangements of atoms

More will be discussed throughout this topic.

4.1.4 Understand how to name compounds relevant to this specification using the rules of international Union of Pure and Applied Chemistry (IUPAC) nomenclature students will be expected to name compounds containing up to six carbon atoms

PREFIXES (BEGINNING OF THE NAME)

Depends on the number of carbons in the parent chain – parent chain is the longest continuous carbon chain
1C – Meth
2C – Eth
3C – Prop
4C – But
5C – Pent
6C – Hex

SUFFIXES