Organic Chemistry: Formulae & Functional Groups

Organic Chemistry: Formulae & Functional Groups in a Snap!

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The key points covered in this video include:
1. Introduction to Hydrocarbons
2. Homologous Series
3. Naming Organic Compounds
4. Functional Groups
5. Organic Formulae
a) General
b) Structural
c) Skeletal
d) Displayed
e) Molecular
f) Empirical

An Introduction to Hydrocarbons

Hydrocarbons are compounds that contain only carbon and hydrogen. They can be further classified as: Alipathic: A Hydrocarbon with carbon atoms joined together in straight or branched chains. e.g. Hexane. Alicyclic: A Hydrocarbon with carbon atoms joined together in a ring structure. e.g. Cyclohexane. Aromatic: A Hydrocarbon with at least one benzene ring in the structure. e.g. Benzene.

Homologous Series

Members of a homologous series are similar. Same functional group, They differ from successive members by a unit of CH2, They have similar chemical and physical properties. Properties show a gradation. Examples: Alkanes: Saturated Hydrocarbons.Alkenes: Unsaturated Hydrocarbons. Alcohols: We see a gradation in the boiling temperatures of the alcohols.

Naming Organic Chemicals

There are millions of chemicals! Some have very similar structures, We use the IUPAC Nomenclature to name the molecules. The name of chemicals can be broken down: Prefix: The first part of the name, Other functional groups. Stem: Main part of the name, Derived from the longest carbon chain. Suffix: Last part of the name, Most important functional group. Other components: Multiplying Prefixes: Indicates the presence of one or more groups. Locants: Numbers and hyphens are used to show the positions of atoms and groups within the molecules.

What is a Functional Group?

A functional group is: The group of atoms that are responsible for the characteristic reactions of a compound.

Using Functional Groups

Functional groups are included in the name of the molecule. They can be contained in different parts of the molecule: Suffix: If they are the most important group. Prefix: If they are an additional functional group.

Alcohol

Prefix: Hydroxy-. e.g. Hydroxybenzene. Suffix: -ol. e.g. Propanol

Aldehyde

Suffix: -al. E.g.: Ethanal.

Alkane

Alkanes can be considered a functional group, but are usually thought of as a key feature of organic molecules. Suffix: -ane. e.g. Propane. Parts of more complicated molecules which resemble alkanes are known as alkyl groups. Alkyl groups have one fewer hydrogen atoms than alkanes, giving them the general formula CnH2n+1. The letter R usually (but not always) represents an alkyl groups.

Alkane

Suffix: -ane. e.g. Propene.

Carboxylic Acid

Suffix: -oic acid. e.g. Propanoic Acid.

Haloalkane

Prefix: F: Fluoro-, Cl: Chloro-, Br: Bromo-, I: Iodo-. e.g. Fluoropropane.

Ketone

Suffix: -one. E.g. Butanone.