chapter 11: Introduction to organic chemisry

organic chemistry

chemistry of organic compounds

features of carbon

• 4 electrons in its outer shell

• can form 4 covalent bonds only

• C-C bonds are strong and non polar

• can form rings

• can form long chain hydrocarbons

formation of organic compounds from inorganic

isomerisation reaction

what did friedrich wohler disprove (1828)

organic compounds were produced by living things only

alkane

• only has single bonds

• e.g methane

alkene

1 double bond between the 2 carbon atoms

e.g ethene

alkyne

has a triple bond

e.g ethyne

empiricle formula definition

simplest ratio of atoms of each element present in a compound

how to calculate empiricle formula

moles= mass/mr

molecular formula

actual number of atoms of each element used

displayed formula

shows every atom and every bond

structural formula

unique arrangement of atoms in a molecule without showing all the bonds

skeletal formula

straight lines represent C-C bonds

uses of wedges

bonds coming out of paper

uses of dotted lines

bonds going into the paper

examples of different types of formula

each type tells you different things

curley arrows

show the movement of electrons

why are curley arrows used

because electrons move to areas of high electron density or slightly positive areas

how are free radicals formed

when a shared pair of electrons in a covalent bond break so each atom has an electron

what are free radicals

fragments of original molecules that have an unpaired electron

reacticityy of free radicals

extremely reactive

nomenclature

system used for naming compound

IUPAC

international union of pure and applied chemistry

root

longest unbranched hydrocarbon chain

syllables used after the root

ane, ene, yne, ol,

uses of prefixes

describe changes made to the root and are added to the beginning of the compound

e.g methyl or cyclo

suffixes

added to the end of the root

functional groups

an atom or group of atoms in an organic molecules responsible for the associated/characteristic reactions of that molecule

prefixes used for halogenoalkanes

fluoro, chloro, bromo and iodo

suffix for ketones

one

e.g propanone or pentanone or hexanone

suffix for aldehydes

al

e.g ethanal , propanal etc

suffix for carboxylic acids

oic acid e.g propanoic acid

naming longer chain hydrocarbons

states where the side chain is and its functional group

define locant

a number used to describe the position of any branching or functional group

history of naming organic compounds

common names were given originating from latin

disadvantages of IUPAC naming system

• some systematic names are too long

• some systematic names are too long so common names are given e.g housane

1 or more hydrogen are substituted naming system

also use numbers to indicate where the halogen atom is

• di= 2

• tri = 3

• tetra = 4

homologous series

a set of organic compounds with the same functional group where the chain length can vary

features of a homologous series

• same general formula

• same functional group

• each member differs

• length affect physical properties

• chain branching decreases the melting point due to decreased packing

isomerism

a compound with the same molecular formula and different arrangement of atoms

structural isomer

same molecular formula and different structural formula

types of structural isomerism

• positional

• fucntional group

• chain

positional group isomerism

same functional group but on different carbons e.g a bromine atom on third or first carbon

functional group isomerism

the functional group is attached to different carbons

chain isomerism

different arrangements of the hydrocarbon chain

stereoisomerism

2 or more compounds that have the same structural formula with different arrangements

E isomerism

priority group is on the opposite side of the alkene

Z isomerism

priority groups are on the same side of the alkene