AS CHEMISTRY UNIT 2: F322
UNIT 2 Chains, Energy and Resources revision guide
Module 1: Basic Concepts and Hydrocarbons
· 2.1.1 Basic Concepts
· 2.1.2 Alkanes
· 2.1.3 Alkenes
Module 2: Alcohols, Halogenoalkanes and Analysis
· 2.2.1 Alcohols
· 2.2.2 Halogenoalkanes
· 2.2.3 Modern Analytical Techniques
Module 3: Energy
· 2.3.1 Enthalpy Changes
· 2.3.2 Rates and Equilibrium
Module 4: Resources
· 2.4.1 Chemistry of the Air
· 2.4.2 Green Chemistry
2.1.1 Basic Concepts
Formulae of Organic Compounds
- Empirical Formula: The simplest whole-number ratio of atoms of each element present in a compound.
- Molecular Formula: The number of atoms of each element in a molecule, e.g. propane C3H8.
- General Formula: The simplest algebraic formula of a member of a homologous series. For example, the general formula of the alkanes is CnH2n+2.
- Structural Formula: A formula showing the minimal detail for the arrangement of atoms in a molecule, e.g. for butane: CH3CH2CH2CH3 or CH3(CH2)2CH3.
- Displayed Formula: A formula showing the relative positioning of all the atoms in a molecule and the bonds between them, e.g. pentane
- Skeletal Formula: A simplified organic formula, with hydrogen atoms removed from alkyl chains, leaving just a carbon skeleton and associated functional groups,
- In structural formulae, the carboxyl group will be represented as COOH and the ester group as COOR
- Benzene can be represented like thisor like this
Functional groups and the naming of organic compounds
- Homologous series: A series of organic compounds with the same functional group, but with each successive member differing by CH2.
- Functional group: The part of the organic molecule responsible for its chemical reactions.
Need to know first 10 members of the alkanes homologous series:
Methane, Ethane, Propane, Butane, Pentane, Hexane, Heptane, Octane, Nonane, Decane.
Type of Compound
· Di- is added to show two identical groups
· Tri- is added to show three identical groups
· Tetra- is added to show four identical groups
When naming substances, always put where the functional group is on the carbon chain.
e.g. this would be named butan-2-ol
- Structural isomers: Molecules with the same molecular formula but…