Chemistry Level 3 External - 3.5 Organic Chemistry

Condensation (substitution)

Two molecules are joined together and a small molecule (H2O or HCl) is released.

Hydrolysis (Esters & Amides)

Water is used to break the amide/ester bond with one part gaining a H and the other an OH.

Structural feature required for optical isomerism

Chiral carbon

Chiral carbon

A carbon bonded to 4 different atoms or groups

Enantiomer

Different forms of an optical isomer

Features of enantiomers

Have a chiral carbon Mirror images Non-superimposable Behave differently in living organisms

How to distinguish between different enantiomers

They rotate the plane of plane-polarised light in opposite directions

Soluble functional groups (1-4 C's)

Alcohols incl diols Amines Carboxylic acids Salts of amines/ carboxylic acids

Br2

Alkene/ alkyne: rapid decolourisation from orange to colourless All other alkyl groups: slow decolourisation from orange to colourless only in the presence of UV light.

MnO4-

Purple → brown ppt

MnO4- / H+

Purple → colourless

Cr2O72- / H+

Orange → green

Amine + damp litmus

Blue stays blue Red turns blue

Carboxylic acid + damp litmus

Blue turns red Red stays red

Carboxylic acid + metal

Fizzing (H2 gas)

Carboxylic acid + metal carbonate/Carboxylic acid + metal bicarbonate

Fizzing (CO2 gas)

Structural (Constitutional) isomers

Two substances with the same molecular formula (number and type of atom) but different structural formula (bond order).

Primary alcohol/ haloalkane

The C directly bonded to the -OH/ -X is bonded to 1 other C

Secondary alcohol/ haloalkane

The C directly bonded to the -OH/ -X is bonded to 2 other C's

Tertiary alcohol/ haloalkane

The C directly bonded to the -OH/ -X is bonded to 3 other C's

Requirements for geometric (cis/trans) isomerism

A C=C Two different atoms or groups bonded to each of the C's of the C=C

C=C required for geometric isomerism

It prevents rotation of the attached atoms (or groups), stopping the two isomers from interconverting.

Two different atoms bonded to each C of the C=C required for geometric isomerism

So that different arrangements in space are possible.

*Markovnikoff addition* Major product explanation

The major product forms when hydrogen is bonded to the less substituted C of the double bond.

*Markovnikoff addition* Conditions required

The alkene is unsymmetrical as there is a different number of H's bonded to each of the C's of the C=C. The addend is also unsymmetrical.

Elimination

Atoms (or groups of atoms) are removed from adjacent carbons, with a double bond forming between those carbons. The molecule changes from saturated to unsaturated.

*Saytzeff elimination* Major product explanation

The major product forms when the hydrogen is removed from the more substituted C.

*Saytzeff elimination* Conditions required

There are two different C's (with different numbers of H's) adjacent to the C bonded to the Cl, Br, OH

Oxidation

Gain O/ increase ON/ lose H/ lose e-

Reduction

Lose O/ decrease ON/ gain H/ gain e-

Acid/Base (NOT neutralisation)

There is a transfer of protons. The acid (_____) is a proton donor and the base (_____) is a proton acceptor.

Polymerisation Definition

The joining together (bonding) of many smaller molecules (monomers).

Substitution

An atom (or group of atoms) are removed from a molecule and a different atom (or group) bonds in its place.

Addition

A C to C double bond (C=C) is broken and atoms (or groups) bond to those C's. The molecule changes from unsaturated to saturated.

Alkane naming

-ane

C-C (fnl gp)

Alkane

Alkene naming

-ene

C=C (fnl gp)

Alkene

Alkyne naming

-yne

Alkyne (fnl gp)

C triple bonded to C

haloalkane naming

fluoro- chloro- bromo- iodo-

-F -Cl -Br -I (fnl gp)

haloalkane

alcohol naming

-anol

-OH (fnl gp)

alcohol

Carboxylic acid naming

-anoic acid

carboxylic acid (fnl gp)

C double bonded to O and single bonded to OH

Amine naming

amino- or -amine

-NH2 (fnl gp)

amine

8C

oct-

7C

hept-

6C

hex-

5C

pent-

4C

but-

3C

prop-

2C

eth-

1C

meth-

ketone (fnl gp)

C double bonded to O

Ketone naming

-anone (number required if >4 C's)

aldehyde (fnl gp)

C double bonded to O and single bonded to H

Aldehyde naming

-anal (no number required)

Amide (fnl gp)

C double bonded to O and single bonded to NH2

Amide naming

-anamide (no number required)

acid chloride (fnl gp)

C double bonded to O and single bonded to Cl

Acid chloride naming

-anoyl chloride (no number required)

ester (fnl gp)

C double bonded to O and single bonded to OR'

Ester naming

-anoyl carboxylate (no number required)