Introduction to Organic Chemistry

Curriculum Outcomes

• recognise and understand the use of a variety of formula types

• understand that an organic compound generally consists of a hydrocarbon component plus a functional group

• recognise the common functional groups• understand and be able to use the IUPAC

nomenclature• understand the formation of homologous series and

understand the similarity of properties

Counting Carbon Atoms

1 – meth2 – eth3 – prop4 – but5 – pent6 – hex7 – hept8 – oct

You must learn to count the longest carbon chain and name it by giving the prefixes shown.

The Alkanes

The alkanes are made by joining carbon atoms together and completing the molecule by adding hydrogen atoms.

Build it!

Create the molecules• Methane• Ethane• Propane• Butane

Representing Organic Molecules

Molecular Formula

• This formula is used where the shape of the molecule is unimportant.

E.g. combustion of propane.C3H8 + 5O2 3CO2 + 4H2O

Representing Organic Molecules

Full Structural Formula

Propane

Representing Organic Molecules

Condensed Structural Formula

CH3 – CH2 – CH3

Propane

Representing Organic Molecules

Skeletal Formula

Propane

At the end of each line it is assumed that there is a carbon and a full compliment of hydrogens, except where an other group is shown

Representing Organic Molecules

Representing 3 Dimensions

Propane

Out of the pageInto the page

On the page

Homologous Series

A homologous series is a series of compounds with• The same general formula• The same functional group

The alkanes are one homologous series.Each successive compound in the series adds one CH2 group.

Functional Groups

• Each homologous series has a unique functional group

• A functional group is a specific group of atoms or bonds that is responsible for the characteristic chemical reactions of the molecules in the homologous series.

Alkenes

The functional group for the alkenes is a carbon carbon double bond.

C=CBuild the alkenes• ethene• propene• butene (can it be done in more than one way?)

Naming

We name organic molecules by numbering the location of the functional groups

Build: • 1-butene • 2-butene• 3-butene

When we name organic molecules we ensure the the numbers are as small as possible, thus 1-butene is the correct name and 3-butene is incorrect.

IUPAC

International Union of Pure and Applied Chemistry

We name organic molecules according to the IUPAC rules.

Alkynes

The functional group for the alkynes is the carbon carbon triple bond.

C Ξ C

Build the model ethyne. This is also called acetylene and is used in welding and cutting torches. The triple bond contains a lot of energy

Alkanols (Alcohols)

The functional group for the alkanols is the hydroxyl group.

-OH

Build one molecule of ethene and one molecule of water.

Location of the –OH group

Alkanols are named according to the location of the functional group.• 1-propanol is a primary alkanol• 2-propanol is a secondary alkanol• Make these two molecules.

More than one –OH group?

Glycerol is an organic molecule that is the byproduct from soap manufacture.

How can we name this molecule according to the iupac rules?

1,2,3-propanetriol

Hydration Reaction

When ethene is heated to 300ºC in the presence of steam and a phosphoric acid (H3PO4) the ethene is hydrated to produce industrial ethanol.

C2H4 + H2O C2H5OH

Simulate this reaction with your molecules

H3PO4 Catalyst

300ºC

Carboxylic Acid

The functional group for the carboxylic acids is

Vinegar contains ethanoic acid. It also has the name acetic acid. Make this molecule.

Carboxylic Acids

When writing the molecular formula, the functional group is written as:

-COOH

Aldehydes

The functional group of the aldehydes is:

The double bonded oxygen is known as a carbonyl group

Aldehydes have a strong odour and are found in many essential oils.

Aldehydes

• Formaldehyde (methaldehyde) was used for many years as a preservative and disinfectant, but is now known to cause cancer

• Make an aldehyde molecule.

An octopus preserved in

formaldehyde

Aldehydes and Alkanols

When we write the condensed structural formula for an aldehyde we write the functional group as:

-CHOThis distinguishes it from the alcohols which are written as:

-COH

Ketones

Ketones contain a carbonyl group like the aldehydes, however it is between two carbon atoms rather than the end of a chain.

R and R’ are the generic way of representing a carbon chain of unknown length

Ketones

Acetone is an important industrial solvent. It is also used as nail polish remover.

Make a molecule of acetone. What do you think its IUPAC name would be?

Ketones

Name the molecule below

Amines

• Amines are biologically significant molecules. • Important amines include amino acids – the

building blocks to make proteins

Amines

The condensed structural formula for the functional group of a primary amine is:

-NH2

Amines

• Make a molecule of methylamine.• Make a molecule of trimethylamine.• Trimethylamine is the molecule associated

with the smell of rotting fish and bad breath.

Haloalkanes

• A single hydrogen can be substituted with a single halogen molecule to make a haloalkane.

• Name each of the haloalkanes below.• Construct a model of one of them

Naming Haloalkanes

When writing the name of a haloalkanes• commas (,) are used to separate numbers, eg,

1,2 or 2,3 • hyphens (-) are used to separate numbers and

letters, eg, 1-chloro and 1,2-dichloro• Name the longest carbon chain.• Carbon atoms bonded to halogen atoms are

given the lowest possible numbers.

Naming Haloalkanes

• Halogens are named before alkyl groups : fluorine atom is named as fluoro chlorine atom is named as chloro bromine atom is named as bromo iodine atom is named as iodo

• For more than one of the same halogen: di = 2 tri = 3 tetra = 4

• For more than one type of halogen, name them alphabetically.

Naming Haloalkanes

Name the following haloalkanes

Branched Chain Alkanes

All organic compounds looked at so far have had only one straight chain of carbon atoms.

In the same way that a halogen can be substituted we can also substitute another organic molecule.

Alkylation

When we substitute one hydrogen for a hydrocarbon chain we call this process alkylation.