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=Alkanes=

Properties
I
 * A homologous series is one which all the members have the same general formula. The neighboring members of the series differ by -CH2-, they show similar chemical properties. They are described a general formula, CnH2n+2. Listed below is a table with the common members in the homologous Series of Alkanes.
 * As the molar mass increases due to the increase of the carbon and hydrogen atoms, the boiling point also increases because of the stronger intermolecular forces like London forces between atoms.

=Isomer=

**Properties**
 * Any of two or more substances that are composed of the same elements in the same proportions but differ in properties because of differences in the arrangement of atoms.
 * The more spherical the isomer, then the lower the boiling point will be because there will be lesser intermolecular forces of attraction on the atom.



=Reactions of Alkanes=

Chemically, alkanes are very unattractive. Their old names was **paraffins**, which literally means "little activity" (from the Latin //parum affinis//). The reasons for this are mainly the relatively strong carbon-to-carbon and carbon-to-hydrogen bonds within them.

** Combustion **

 * an alkane reacts with Oxygen
 * Example: CH4+2O2-->CO2 + 2H2O
 * there are two types, Complete and Incomplete



Halogenation

 * an alkane reacts with a halogen
 * where a Carbon-Hydrogen bond is broken and a Carbon-Halogen bond is formed
 * most frequently react with alkanes are chlorine and bromine
 * Example: CH4+Cl2-->CH3CL+HCl

=Alkenes=

**Properties**
 * an unsaturated chemical compound
 * contains at least one carbon-to-carbon double bond
 * simplest alkene is ethylene C 2 H 4
 * has the general formula C n H 2n
 * has a lot of kinds of reactions
 * as the molar mass increases due to the increase of the carbon and hydrogen atoms, the boiling point also increases because of the stronger intermolecular forces like London forces between atoms
 * like alkanes, alkenes are not soluble in water but are soluble in organic solvents
 * are unsaturated because they still can undergo addiction reactions across the double bond
 * either non-polar or have very low polarity

= =

**Reactions of Alkenes**
Combustion
 * During combustion, Alkenes just like Alkanes, burn in excess oxygen to give carbon dioxide and water as the products of complete combustion.

**C** **2** **H** **4** **+ 3O** **2** **→ 2CO** **2** **+ 2H** **2** **O**

Hydrogenation
 * the reaction is carried out under pressure at a temperature of 200 °C in the presence of a metallic catalyst
 * common industrial catalysts are based on platinum or nickel
 * the simplest example of this reaction is the catalytic hydrogenation of ethylene to yield ethane:

**CH** **2** **= CH** **2** **+ H** **2** **→ CH** **3** **-CH** **3**

Halogenation
 * the reaction of the carbon-carbon double bond in alkenes with hydrogen in the presence of a metal catalyst. This is called hydrogenation. It includes the manufacture of margarine from animal or vegetable fats and oils.
 * Ethene and fluorine - Ethene reacts explosively with fluorine to give carbon and hydrogen fluoride gas.

**CH** **2** **= CH** **2** **+ 2F** **2** **→ 2C +4F**

Hydration
 * the production of alcohols by the direct hydration of alkenes - adding water directly to the carbon-carbon double bond.
 * Manufacturing ethanol - Ethanol is manufactured by reacting ethene with steam. The reaction is reversible.
 * Only 5% of the ethene is converted into ethanol at each pass through the reactor. By removing the ethanol from the equilibrium mixture and recycling the ethene, it is possible to achieve an overall 95% conversion.

**CH** **2** **= CH** **2** **+ H2O → CH** **3** **CH** **2** **OH**

Polymerization
 * the polymerization of alkenes to produce polymers like poly(ethene) (usually known as polythene, and sometimes as polyethylene), poly(propene) (old name: polypropylene), PVC and PTFE.
 * **Low density polyethene**
 * This is an example of addition polymerization.
 * An addition reaction is one in which two or more molecules join together to give a single product. During the polymerization of ethene, thousands of ethene molecules join together to make poly(ethene) - commonly called polythene.

**nCH** **2** **= CH** **2** **→ [-CH2-CH2-]**

 * Conditions
 * Temperature - about 200°C
 * Pressure - about 2000 atmospheres
 * Initiator - a small amount of oxygen as an impurity

Sources: http://www.answers.com/topic/isomer http://www.btinternet.com/~melee3d/revision/chemistry/images/naming-pentane.png Chemistry Book http://www.chemguide.co.uk/organicprops/alkanes/oxygen.html http://www.tutorvista.com/chemistry/alkanes-alkenes-alkynes-interactive http://www.chemguide.co.uk/organicprops/alkenemenu.html