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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…

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2.1.1 Basic Concepts
Formulae of Organic Compounds
Terms
- 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…

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Terms
- 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,…

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- Structural isomers: Molecules with the same molecular formula but with different
structural arrangements of atoms.
- Stereoisomers: Compounds with the same structural formula but with different
arrangement of the atoms in space.
- E/Z isomerism: A type of stereoisomerism in which different groups attached to
each C=C double bond…

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actual amound, in mol, of product
% yield =theorectical amount, in mol, of product ×100



Atom Economy
molecular mass of the desired products
atom economy =
sum of molecular masses of all products ×100



- All addition reactions have a 100% atom economy
- The higher the atom economy the…

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BOILING POINTS
Effect of chain length
- As the chain length increases, so does the boiling point.
- This is because the intermolecular forces between molecules get stronger.
- In longer alkanes, there are more points of contact between the molecules leading
to more van der Waals forces.
- Therefore…

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- Catalyst: a substance that increases the rate of a chemical reaction without being
used up in the process

Short chained alkanes are in higher demand, therefore cracking is a
process used to fulfil this demand.
- Short chained alkanes are used as fuels.
- Short chained alkenes are in…

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Producing cyclic hydrocarbons
Aliphatic hydrocarbons can be converted into cyclic or aromatic hydrocarbons in a process
sometimes known as reforming.




Improving fuels
- Research octane number (RON) rates how well a fuel burns. Fuels with near 100
ratings burn more efficiently. Heptane burns poorly and has an octane rating of…

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Halogenation of alkanes
Alkanes react with halogens in the presence of UV radiation or at a temperature of about
300°c. For example methane reacts with chlorine to produce chloromethane:
CH4 + Cl2 CH3Cl + HCl
This is radical substitution. Covalent bonds are broken by Homolytic fission to form
radicals. A…

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Properties of Alkanes
Term
- Pi( )-bond: the reactive part of a double bond formed above and below the plane of
the bonded atoms by the sideways overlap of p-orbitals.
- Sigma( )-bond
In the formation of the double bond:
- A -bond is formed directly between to carbon atoms…

Comments

eki

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Thank you so much. These are so helpful, well written and useful. 

KoolKat

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This was soooooo helpful 

Thanks


Shaur Budree

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THANKS MAN

 

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