4.1 Basics Concepts And Hydrocarbons

1 carbon= meth- 2 carbons= eth- 3 carbons= prop- 4 carbons=but- 5 carbons=pent- 6 carbons=hex- 7 carbons=hept- 8 carbons=oct- 9 carbons=non- 10 carbons=dec-

The system for naming compounds

A series of organic compounds having the same functional group but with each successive member differing by CH2

1carbon= methyl- 2carbons=ethyl- 3carbons=propyl- 4carbons=butyl- 5carbons=pentyl- 6carbons=hexyl- 7carbons=heptyl- 8carbons=octyl- 9carbons=nonyl- 10carbons=decyl-

CnH2n+1 -n=number of carbons

CnH2n+2 -n=number of carbons

CnH2n -n=number of carbons

CnH2n+1 OH -n=number of carbons

-a compound containing carbon and hydrogen joined together in straight chains,branched chains or non-aromatic rings

-an aliphatic compound arranged in non-aromatic rings with or without side chains

A compound containing a benzene ring

Compounds with the same molecular formula but different structural formulae

-the alkyl groups are in different places -the functional group can be bonded to different parts of the parent chain -the functional group could be different

-organic compounds with the same molecular formula and structural formula but having different arrangements of atoms in space

-each bonding atom receives one electron from the bonded pair, this forms 2 radicals -and the breaking of a covalent bond

-one bonding atom receives both electrons from the bonded pair and the covalent bond is broken -this results in a cation and anion being formed

A species with an unpaired electron

They are saturated hydrocarbons that contain single C-C and C-H bonds as sigma bonds (single) They are free to rotate

An overlap of orbitals directly between the bonding atoms

-they have a tetrahedral shape with a bond angle of 109.5

-carbon and hydrogen have very similar electro negativity values so alkane molecules are non-polar -however as electrons are constantly moving at times there may be a lack of balance in charge distribution, causing an instantaneous dipole which will induce dipoles in neighbouring molecules -this is called an induced dipole-dipole interaction or London force

-as an alkane chain gets longer its molecular mass increases -larger molecules also have more surface area contacts between adjacent molecules -this increases the number of induced dipole-dipole interactions (London forces) -so more energy is needed to overcome the intermolecular attraction so that the alkane can change state ,so the boiling point becomes higher the longer the carbon-chain length is

-the more branched a compound is the fewer surface interactions there are between molecules -therefore branched molecules have fewer induced dipole-dipole interactions compared to a straight-chain isomer with the same molecular formula -so branched molecules will have a lower boiling point than the equivalent straight chain isomer

-all the covalent bonds in alkane molecules have high bond enthalpies- so a large amount of energy is required to break the bonds -the carbon-hydrogen sigma bonds have a very low polarity as the electronegativities of carbon and hydrogen are almost the same