Introduction to Organic Chemistry

• Organic chemistry mainly concerns the properties and reactions of hydrocarbons, a series of compounds with similar structures and formulas with different representations.
• Nomenclature is the set of rules that outline how different organic compounds should be named and how their formulas are represented.
• There are six different ways to represent organic compounds: empirical formula, molecular formula, general formula, structural formula, displayed formula and skeletal formula.
• Empirical formula is the simplest whole number ratio of atoms of each element in a compound.
• Molecular formula is the true number of atoms of each element in a compound.
• General formula is the formula that all members of a homologous organic series follow.
• Structural formula shows the structural arrangement of atoms within a molecule.
• Displayed formula shows every atom and bond in an organic compound.
• Skeletal formula shows only the bonds in a compound and any non-carbon atoms. The vertices are carbon atoms and hydrogen is assumed to be bonded to them unless stated otherwise.
• Organic compounds are often part of a homologous series, in which all members follow a general formula and react in a very similar way.
• Each consecutive member of a homologous series differs by CH2 and there is an increase in boiling points as chain length increases.
• Each homologous series has a functional group that allows the molecule to be recognised as being able to react chemically in a certain way as a result of that group.
• Alcohols have the functional group R-OH and the IUPAC ending -ol.
• Phenols have the functional group hydroxyl (-OH) attached to a carbon atom in a benzene ring. They have the IUPAC ending -phenol.
• Ethers have the functional group of an oxygen atom which forms single bonds with two carbon atoms. They have the IUPAC ending -ether.
• Aldehydes have the functional group R-CH=O. They have the IUPAC ending -al.
• Ketones have the functional group R-C(=O)-R’. They have the IUPAC ending -one.
• Carboxylic acids have the functional group -COOH. They have the IUPAC ending -oic acid.
• Esters have the functional group R(=O)-O-R’. They have the IUPAC ending -ate.
• Compounds are named according to rules laid out by the International Union of Pure and Applied Chemistry (IUPAC). This ensures each compound is universally named the same to avoid potentially dangerous confusion.
• The first 10 prefixes are meth, eth, prop, but, pent, hex, hept, oct, non, dec. These prefixes represent the length of the longest unbroken chain of carbon atoms in a compound.
• The ending of the compounds name tells you the functional group present. If there are multiple functional groups present, these are added as suffixes.
• The suffix for an alkane is -ane.
• The suffix for an alkene is -ene.
• The suffix for an alcohol is -ol.
• The suffix for a carboxylic acid is -oic acid.
• The suffix for a ketone is -one.
• The suffix for an aldehyde is -al.
• The suffix for an ester is -ate.
• The suffix for an amine is -amine.
• If a halogen is present, it is replaced by a prefix (e.g. chlorine functional group would have a chloro- prefix).
• Carbon side chains that are branches from the longest carbon chain are represented by a prefix at the start of the word. These alkyl groups are made using stems (e.g. meth, eth) and the suffix -yl (e.g. methyl).
• Functional groups and side chains should be given a number corresponding to the carbon they are attached to.
• Numbers in a chemical name should be separated by commas.
• Numbers and words in a chemical name should be separated by hyphens.
• If there are multiple versions of the same side chain/functional group in a chemical name, a corresponding prefix should be added depending on how many there are (e.g. two is -di).
• The carbon chain is numbered in ascending order from the end of the chain nearest a functional group.
• If multiple prefixes are present in a chemical name, they are included in alphabetical order.
• The main types of reaction mechanisms are: addition, substitution, oxidation, reduction and polymerisation.
• In an addition reaction, the reactants combine to form a single product.