BePaPhil


 * HOMOLOGOUS SERIES**
 * - a series of organic compounds that have similar general formula, and possess similar chemical properties due to the presence of the same functional group (which are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reactions regardless of the size of the molecule it is part of), and shows a gradation in physical properties as a result of increase in molecular size and mass.**


 * Isomers**
 * **Chemical species/molecules that have the same number and types of atoms, but have different properties**
 * Structural Isomers**
 * Geometrical Isomers**

Example of isomers and their boiling points: pentane 36.1 °C 2-methylbutane 27.7 °C 2,2-dimethylpropane 9.5 °C

Straight chains generally have higher boiling points than branched chains because they line up together better, increasing their intermolecular force or attraction.

Reactions of Alkanes Alkanes have a low reactivity due to their relatively strong C-C and C-H bonds. They are unlike the other hydrocarbons that have double or triple bonds, which allow them to split their double or triple bonds and form single bonds. Because they have no functional groups, they are composed only of Carbons with single bonds and Hydrogens, making some of the isomers non-polar. They react only very poorly to ionic or polar compounds.

Combustion: Complete Combustion > ex. Propane and oxygen yields carbon dioxide and water C3H8 + 5O2 → 3CO2 +4H2O
 * Complete combustion of an alkane produces water and carbon dioxide

Incomplete Combustion > ex. Methane and oxygen yields solid carbon and water > CH4(g) + O2(g) → C(s) + 2H2O(g)
 * Incomplete combustion of an alkane produces carbon and/or carbon monoxide and water

**HALOGENATION**


 * it is the replacement of one or more hydrogen atoms in an organic compound by a halogen ( //fluorine, chlorine, bromine, iodine// )
 * Unlike the complex transformations of combustion, the halogenation of an alkane appears to be a simple **substitution reaction** in which a C-H bond is broken down and a new C-X bond is formed ( X representing a halogen )
 * A simple example of the halogenation reaction would be the chlorination of methane, that goes like this:

CH 4 + Cl 2 + //energy// > CH 3 Cl + HCl

*Since only two covalent bonds are broken ( C-H & Cl-Cl ), and two new covalent bonds are formed ( C-Cl & H-Cl ), this reaction would seem to be the ideal case for mechanistic investigation and speculation. HOWEVER, one complication is that all the hydrogen atoms of an alkane may undergo substitution, resulting in a mixture of products

The following facts must be accomodated by any reasonable mechanism for the halogenation reaction. 1. The reactivity of the halogens decreases in the following order: F 2 > Cl 2 > Br 2 > I 2. 2. We shall confine our attention to chlorine and bromine, since fluorine is so explosively reactive it is difficult to control, and iodine is generally unreactive. 3. Chlorinations and brominations are normally exothermic. 4. Energy input in the form of heat or light is necessary to initiate these halogenations. 5. If light is used to initiate halogenation, thousands of molecules react for each photon of light absorbed. 6. Halogenation reactions may be conducted in either the gaseous or liquid phase. 7. In gas phase chlorinations the presence of oxygen (a radical trap) inhibits the reaction. 8. In liquid phase halogenations radical initiators such as peroxides facilitate the reaction.

 Sources:

 http://en.wikipedia.org/wiki/Homologous_series

 http://en.wikipedia.org/wiki/Functional_group http://www.gcsescience.com/o24.htm [] [] http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/funcrx1.htm
 * http://chemistry.about.com/od/chemistryglossary/a/isomerdef.htm**

Alkene: Compared to Alkane Alkane and Alkenes are made of hydrogen and carbons, but Alkanes only have single bonds while Alkenes have one double bond. An alkane also is a saturated hydrocarbon, while an alkene is unsaturated.

For Alkenes, with every carbon atom, there is twice as much hydrogen atoms in the molecule.

Reactions of Alkenes:

Combustion Ethene + Oxygen yields carbon dioxide and water. code C2H4  +   3 O2   ==>   2 CO2   +   2 H2O code CONDITION: requires fire

Hydrogenation Ethene + Hydrogen yields Ethane code H2C=CH2  +   H2      ==>             CH3CH3

code Catalyst: Nickel Catalyst and 180 degrees

Halogenation (monosubstituted)

Halogenation (disubstituted) Ethene + Chlorine yields DiChloroEthane code H2C=CH2  +   Cl2       ==>     CH2Cl CH2Cl code

Hydration Ethylene + steam yield ethanol code H2C=CH2  +   H2O       ==>     C2H5OH

code Catalyst: Phosphoric acid/ Sulfuric acid and 180 degrees

Polymerization Ethane yields Polythene

code n(C2H4)        ==>             (C2H4)n

Sources: http://www.ucc.ie/academic/chem/dolchem/html/dict/alkenes.html http://www.chemguide.co.uk/organicprops/alkenes/background.html code

Organic Derivatives

R stands for the alkyl group (methyl, ethyl, etc)

Alcohol General Formula: R-OH Naming: The -e at the end of the alkane is replaced by -ol Tiers: Primary Formula: H R-C-OH H Secondary Formula: H R-C-OH R Tertiary Formula: R R-C-OH R

Halogenoalkanes General Formula: R-X (where X represents F,CL,Br or I) Naming: fluoroi-, chloro-, bromo-, iodo- is placed in front of the alkane Tiers: Primary Formula: H R-C-X H Secondary Formula: H R-C-X R Tertiary Formula: R R-C-X R

Aldehydes General Formula: R-CHO Naming: The -e at the end of the longest chain alkane is replaced by -al

Ketone General Formula: R-COR' (R' stands for the same alkyl group as R or a different alkyl group) Naming: The -e on the end of the longest chain alkane is replaced by -one

Carboxylic acid General Formula: R-COOH Naming: The -e on the end of the longest chain alkane is replaced by -oic acid

Esters General Formula: R-COOR' Naming: The -e on the end of the longest chain alkane is replaced by -oate

Amines General Formula: R-NH2 Naming: The -e on the end of the longest chain alkane is replaced by -amine

Sources: http://www.angelfire.com/bc2/OrgChem/amines.html http://www.angelfire.com/bc2/OrgChem/esters.html


 * Group || Type of IMF || Relative boiling point || Soluble in water || Volatility ||
 * Alkanes || Van der Waals' || very low || no ||  ||
 * Halogenoalknes || weak dipole-dipole || low || no ||  ||
 * Aldehydes || dipole-dipole || moderate || yes ||  ||
 * Ketones || dipole-dipole || moderate || yes ||  ||
 * Alcohols || H-bonding || high || yes ||  ||
 * Carboxylic acids || H-bonding || high || yes ||  ||

Reactions of Organic Derivatives

Alcohols dichromate ions, dilute sulfuric acid, heat are needed to oxidize alcohols

- Primary alcohols need an acidified aqueous solution of potassium dichromate to oxidize. The product is an aldehyde and then oxidized futher to from a carboxylic acid. - Secondary alcohols need an aqueous acidified dichromate solution. The product is a ketone. - Tertiary alcohols need to have their carbon chain disrupted to oxidize.

Halogenoalkanes Substitution displacement of the halogen diff halogen diff bond strength/reactivity the substitutes are called nucleophiles

SN2-substitution nucleophilic bimolecular Primary, Secondary bimolecular because the rate of reaction is based on the concentration of 2(alkyl halide and nucleophile) no steps from one side, nucleophile while halogen leaves on the other side there is a transition state where the bonds form and break; most energy nucleophile->alkyl halide->halogen

SN1-substitution nucleophilic unimolecular Tertiary, Secondary unimolecular because the rate of reaction is based only on the concentration of alkyl halide step by step the halogen has to leave the halide alkyl(slow step) before the nucleophile can join in(fast step) alkyl halide->halogen alkyl<-nucleophile

Nucleophilic substitution reactions involve heterolytic fission since the electrons of an atom or molecule are "donated" to another.