Revision notes for AQA AS Chemistry Units 5 and 6- Organic Chemistry and Alkanes

Unit 5 and 6 revision notes for AQA syllabus

HideShow resource information
Preview of Revision notes for AQA AS Chemistry Units 5 and 6- Organic Chemistry and Alkanes

First 228 words of the document:

The physical and chemical properties of organic compounds depend on two factors:
The number and arrangement of carbon atoms in the molecule.
The greater the number of carbon atoms, the larger the Van der Waal's forces and the
higher the melting points, boiling points and viscosity.
The functional groups in the molecule
A functional group is a specific atom or group of atoms which confer certain physical and
chemical properties onto the molecule.
Type of compound Nature of functional group
Alkane C-C and C-H single bonds only (ie no functional group)
Alkene C=C double bond
Haloalkane Cl, Br or I atom attached to a carbon atom
Most organic compounds can be named systematically by the IUPAC method.
In order to describe completely an organic molecule, three features must be described:
The longest carbon chain on the molecule.
The length and position of any branches on the molecule.
The nature and position of any functional groups on the molecule.
The longest straight chain on the molecule
The longest straight chain on the molecule is indicated by one of the following prefixes:
Number of carbon atoms in the chain Prefix
1 Meth-
2 Eth-
3 Prop-
4 But-

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

6 Hex-
Homologous Series Prefix or suffix Example
Alkanes -ane Propane
Alkenes -ene Propene
Branched Groups -yl Methyl propane
Haloalkanes Chloro- Chloro-propane
With Alkenes you need to specify where the double bond is and use the numbers from there.
Branched Group
1 No prefix
2 Di-
3 Tri-
4 Tetra-
5 Penta-
Structural isomers are molecules which have the same molecular formula but a
different arrangement of covalent bonds.…read more

Page 3

Preview of page 3

Here's a taster:

Type of Formula What it shows you Example
General formula An algebraic formula that can CnH2n+2
describe any member of a
family of compounds
Empirical formula The simplest ratio of atoms of C2H5
each element in a compound.
Molecular formula The actual number of atoms of C4H10
each element in a molecule
with any functional groups
Structural formula Shows the atoms carbon by CH3CH2CH3CH2
carbon with attached
hydrogens and functional
groups.…read more

Page 4

Preview of page 4

Here's a taster:

How does it work?
First the crude oil is vaporised at about 350 degrees
The vapourised crude oil goes into the fractionating column and rises up through
the trays. The largest hydrocarbons don't vaporise at all because their boiling
points are too high. They just run to the bottom and form residue.
As the crude oil vapour goes up the fractionating column it gets cooler. Because
of the different chain lengths each fraction condenses at a different temperature.…read more

Page 5

Preview of page 5

Here's a taster:

Kerosine or paraffin Plane fuel, petrochemicals
Diesel or gas oil lorry, central heating fuel
Mineral/lubricating oil Lubrication,
Fuel oil Ship fuel, power stations
Wax and grease Candles, grease, polish
Bitumen or tar Road surfaces, roofing
Type of cracking Thermal Catalytic
Conditions High temperature (400 ­ High temperature (450 oC)
900 oC)
High pressure (70 atm) Slight pressure ( > 1 atm)
Zeolite catalyst
Main products High percentage of alkenes Motor fuels (ie branched
Aromatic hydrocarbons
Alkanes as fuels
If you have complete combustion…read more

Page 6

Preview of page 6

Here's a taster:

The greenhouse gases are methane, carbon dioxide and water vapour.…read more


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »