INTRO IN ORGANIC CHEMISTRY

displayed formula

shows how all atoms are arranged and all the bonds between them

functional group o

a group of atoms responsible for the characteristic of the molecule

nomenclature

naming molecules using specific rules known as IUPAC

molecular formula

gives the actual number of atoms of each element in a molecule

structural formula

shows the atoms CARBON BY CARBON with the attached hydrogens and functional groups in WRITTING and DOES NOT SHOW BONDS

empirical formula

smallest whole number ratio of atoms of each elements in a compound

general formula

algebraic formula that can describe any member of a family of compounds AKA homologous series

Homologous series

a family of compounds that have the same functional group and general formula, consecutive members of a homologous series differ by -CH₂- and you can predict their chemical properties

SKELETAL FORMULA

shows bonds of the carbon skeleton representing carbon atoms as lines and hydrogen atoms as vertices USEFUL FOR CYCLIC HYDROCARBONS

alkane general formula

C_nH_2n+2

Alkanes are saturated hydrocarbons

carbons have 4 bonds and molecule only contains hydrogen and carbon

halogenoalkanes

• similar to alkanes expect at least 1 hydrogen is replaced with a halogen atom

• prefix- FLUORO-/CHLORO-/BROMO-/IODO-

CYCLOALKANES

• a ring of carbon atoms with 2 hydrogens attached to each

• they have fewer hydrogen atoms that other alkanes therefore have a different general formula: C_nH_2n
  saturated

• prefix: CYCLO-

• suffix: -ANE

branched alkanes

• the main carbon chain is the longest one

• the branched chains are called ALKYL groups

alkenes

• hydrocarbons with a carbon carbon double bond

• general formula: C_nH_2n

• unsaturated because of double bond as carbon could form a 4th bond, making them fairly reactive

alcohols

• -OH/ hydroxyl functional group

• suffix: -ol

• general formula C_nH_2n+1OH

aldehydes

• END CARBON HAS A DOUBLE BOND TO OXYGEN AND SINGLE BOND TO HYDROGEN

• suffix:-al

• general formula R-CHO

ketones

• MIDDLE CARBON HAS DOUBLE BOND TO OXYGEN

• general formula R-C=O-R’

CARBOXYLIC ACID

• functional group COOH

• suffix: -OIC ACID

• general formula R-COOH

IUPAC system

allows scientific ideas to be communicated across the globe more effectively

nomenclature rules:

• count the carbons in the longest continuous chain that contains the functional group

• the main functional group of the molecules usually gives the suffix

• number the carbons in the lowest carbon chain so that the carbon with the main functional group attached has the lowest possible number

• write the carbon number that the functional group is on before the suffix EG: pentan-2-ol

• any side chains or less important functional groups are added as prefixes at the start of the name in alphabetical order, with the number of the carbon atom each is attached to

• if there’s 1 or more identical side chains/ functional groups use di-, trio- or tetra- before that part of the name

cycloalkanes have the same name as their straight chain equivalents

but with cyclo- attached to the front

if the cycloalkane has an alkyl group attached

its added as a alkyl prefix

functional group priority list

(lowest) HALOGENS → ALKYL → ALKENES → OTHER FUNCTIONAL GROUPS (highest)

mechanisms break reactions down

into a sequence of stages

reaction mechanism diagrams show how molecules react together

by using curly arrows to show which bonds are made/broken

structural isomers

molecules with the same molecular formula but different structural formula

types of structural isomers

• chain

• position

• functional

chain isomers

same functional groups but different arrangement of the carbon skeleton

position isomers

same carbon skeleton but different placement of the functional group

functional group isomers

same atoms arranged into different functional groups

stereoisomers

same structural formula but different arrangement of atoms in space

types of stereoisomers

• E/Z

• geometric

E/Z isomerism

seen in C=C molecules

carbon atoms in a C=C and all atoms attached to them are on the same plane

the molecule is planar (trigonal planar to be exact)

in larger alkenes only the C=C unit is planar

atoms cannot rotate around C=C bonds

E-isomers

the same atoms are opposite/ diagonal each other

Z-isomers

the same atoms are on the same side as each other

Cahn-ingold-prelog priority rule helps identify E/Z isomers

• start by assigning a priority to the two carbon atoms in a double bond

• the atom with the higher atomic number of each carbon is given a higher priority

• if the atoms directly bonded to each carbon ar the same then you look at the next aotm in the groups to work out which has the higher priority

• to work out which isomer you have, look at how the two higher proirity groups are arranged.

• if they’re positioned across the double bond from each other (diagonal) then tis an E isomer

• if they’re positioned both above or both below the double bond you have Z-isomer