Core organic chemistry

general formula def

the simplest algebraic formula of a member of a homologous series) e.g. for an alkane: CnH2n+2

structural formula definition

the minimal detail that shows the arrangement of atoms in a molecule) e.g. for butane: CH3CH2CH2CH3 or CH3(CH2)2CH3

displayed formula

the relative positioning of atoms and the bonds between them e.g. for ethanol:

Skeletal formula definition

the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups e.g. for butan-2-ol:

Homologous series definition

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

Functional group definition

a group of atoms responsible for the characteristic reactions of a compound

Alkyl group formula

CnH2n+1

Aliphatic definition

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

Alicyclic meaning

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

Aromatic meaning

A compound containing a benzene ring

What is a benzene ring

An aromatic functional group characterized by a ring of six carbon atoms, bonded by alternating single and double bonds.

Saturated meaning

Only contains single carbon-carbon bonds

Unsaturated

The presence of multiple carbon-carbon bonds including C=C C=-C and aromatics rings

Structural isomer definition

Compounds with the same molecular formula but a different structural formula

Alkane definition

Saturated hydrocarbons containing single C-C and C-H sigma bonds

Why is there a tetrahedral shape around each carbon in an alkane

4 bonding regions and zero lone pairs result in equal repulsion and a 109.5 degree between each carbon

Why does boiling point increase in longer chain alkanes

higher surface area so more contact points so more

Why does boiling point decrease with more branching

Branched alkanes has relatively small surface area for contact points, so less London's dispersion force act among molecules

Why do alkanes have relatively low reactivities?

Due to the strong C-C and C-H bonds in the molecules that require a lot of energy to overcome or in the presence of strong catalysts

Complete combustion formula

Alkane+oxygen→ carbon dioxide+ water

Incomplete combustion formula

Alkane+oxygen→ carbon monoxide/soot+ water

sigma bond

head on overlap of two p orbitals

pi bond

adjacent p orbitals overlap in a sideways orientation forming a cloud of electron density above and below the plane

what is a double bond made of

sigma and pi bond

is a sigma or pi bond stronger

sigma

what bond breaks with a double to single bond

pi bond as it is weaker

free radical mehcanism steps

initiation with Uv light to form radicals

propagation in which radicals and pairs make radicals and pairs

termination starts with radicals ends with pairs

stereoisomer definiton

same structural formula but different arrangement of atoms in space

E/Z isomerism requirements

C=C double bond, different groups attatched to each carbon of the double bond

position isomers

strucutral isomers that can be viewed as differing only on the position of a functional group, substituent, or some other feature on the same "parent" structure

chain isomers

made up of two or more carbon or other compounds with the same molecular formula but different atomic arrangements, or branches

functional group isomers

molecules with the same molecular formula, but different functional groups

naming E/Z isomers rules

draw line in middle of C=C, assign priority on each side acoridng to Mr (directly bonded to C). same side Z opposite E

why do E/Z isomers need a double bond

because it restricts free rotation and means the groups attatched to the carbons can’t move

cis-trans isomers

a type of E/Z where two of the substituent groups on the C=C bond are the same

electrophilic meaning

electron pair acceptor

nucleophilic meaning

electron pair donor

why are alkenes more reactive than alkanes

pi bonds are weaker so need less energy to overcome

what is a curly arrow used for?

showing where an electron pair is going. go from high to low electorn density

what is electrophilic addition

a reaction in which a substrate is initially attacked by an electrophile, and the overall result is the addition of one or more relatively simple molecules across a double bond

what is a reaction mechanism

a series of steps that show how a reaction takes place

Marvovnikoff’s rule

during electrophilic addition to alkenes/alkynes the h atom in the electrophile will be added to the C with less C/more H

primary carbocation 1°

the carbon which carries the positive charge is only attached to one other alkyl group

secondary (2°) carbocation

the carbon with the positive charge is attached to two other alkyl groups, which may be the same or different

tertiary (3^o) carbocation

the positive carbon atom is attached to three alkyl groups

order of stability for carbocations and why

tertiary most primary least bceause the more chains the bigger the inductive effect

what is the inductive effect

The effect on electron density in one portion of a molecule due to electrophilic or nucleophilic groups elsewhere in the molecule

what determines the major product adding a hydrogen halid to an alkene

the C bonded to the least Cs

what happens in heterolytic fission

the pair of shared electrons is taken by one of the atoms

what happens in homolytic fission

the pair of electrons is split between the separated atoms