REVISIONORGANIC CHEMISTRY

HYDROCARBON

A bond or an atom or a group of atoms that determine(s) the physical and chemical properties

of a group of organic compounds

HOMOLOGOUS SERIES

FUNCTIONAL GROUP

A series of organic compounds that can be described by the same general formula

Organic compounds that consist of hydrogen and carbon only

alkanes alkenes alkynes

haloalkanes alcohols

aldehydes ketones

esters

Carboxylic acids

2 2n nC H 2n nC H

2 2n nC H

2 1n nC H X 2 1n nC H OH

R CHO 'R CO R

'R COO R

R COOH

Single bonds

Double bonds

Tripple bonds

halideshydroxyl

Carbonyl with hydrogen Carbonyl

Carbonyl with

oxygen

Carbonyl with

hydroxyl

IUPAC NAMES

1

2

3

4

MET

ET

PROP

BUT

PENT

HEX

HEPT

5

6

7

Fx group

-ol-al

-one-anoate

-noic acid

IUPAC NAMES

Number C# Fx group

-ol-al

-one-anoate

-noic acid

ditri

tetra#-yl

anenyn

1,2

IUPAC NAMES2-methylbut-1-ene

2-methylprop-1-ol

1-bromo-2-chlorocyclopentane

4,4-dimethylpent-2-yne

3-methylbutanal

IUPAC NAMESpent-2-one

Propanoic acid Methyl butanoate

When naming halo alkanes, the halogen atoms do not get preference over alkyl groups – numbering should start from the end nearest to the first substituent, either the alkyl group or the halogen.

In halo alkanes, where e.g. a Br and a Cℓ have the same number when numbered from different ends of chain, Br gets alphabetical preference

When writing IUPAC names, substituents appear as prefixes written alphabetically (bromo, chloro, ethyl, methyl), ignoring the prefixes di- and tri.

IUPAC NAMES

SATURATED COMPOUNDS

UNSATURATED COMPOUNDS

Compounds in which there are no multiple bonds between C atoms in their hydrocarbon chains. .

Compounds with one or more multiple bonds between C atoms in their hydrocarbon chains.

+Br2

5 10

You have two test tubes with compound X an Y, respectively.

Both have a molecular formula

of C H , but you suspect that X might be saturated.

You want to set up an experiment to test your hypothesis

Wra

ite an investigative question

Write a list of chemicals and apparatus that you will use.

What safety precautions will you follow

Write down the procedure for your experiment

How will you use your obs

b

c

d

e

ervations to justify your hypothesis

Write down the IUPAC name of compound Y.f

MOLECULAR FORMULAA chemical formula that indicates the type of atoms and the

correct number of each in a molecule

A structural formula of a compound shows which atoms are attached to which within the molecule. Atoms are

represented by their chemical symbols and lines are used to represent ALL the bonds that hold the atoms together.

STRUCTURAL FORMULA

This notation shows the way in which atoms are bonded together in the molecule, but DOES NOT SHOW ALL bond lines.

CONDENSED STRUCTURAL FORMULA:

ISOMERS

STRUCTURAL Organic molecules with the same molecular formula, but different structural formulae.

CHAIN Same molecular formula, but different types of chains

POSITIONAL

Same molecular formula, but different positions of the side chain, substituents or functional groups on the parent chain,

ISOMERS

6 14C HHexane

2-methylpentane2,2-dimethylbutane

In the follwong reaction,

give the name of compound X.           

Propyne

Propan 1 ol

Propane

Propan 2 ol

A

B

C

D

propene Compound X

QUESTIONS ABOUT REACTIONS when you have the REACTANTS…

In the follwong reaction,

give the name of compound X.           

Propyne

Propan 1 ol

Propane

Propan 2 ol

A

B

C

D

propene Compound X

QUESTIONS ABOUT REACTIONS when you have the REACTANTS…

Some organic reactions are shown in the flow diagram below

Name the type of reactions illustrated by A, B, C and D

Use condensed structural formulae and write a balanced equation for reaction

  

a . 

b C.

c W

3 7

rite down the structural formula for compound X

 In order to obtain product Y, C H Br is heated with a concentrated solution of KOH

under reflux.

Use condensed structural formulae to write a bald anced

3 7

equation for the reaction

group of learners decided to heat C H Br with dilute sodium hydroxide, instead of the

concentrated potassium hydroxide, under reflux

Write down the IUPAC name of the or

 A

e ganic compound that they will obtain.

QUESTIONS ABOUT REACTIONS when you have the REACTANTS & PRODUCTS

3 2 2 3 2 2

3 2 2 3 2 2

elimination 

(see below)

1

a A addition

B substutution

C substutution

D

b CH CH CH Br KOH CH CH CH OH KBr

c propene

d CH CH CH Br KOH CH CH CH KBr H O

e propan ol

PHYSICAL ATTRIBUTESalkanes alkenes alkynes

halo alkanes

halo alkanes

alcohols

alcohols

aldehydes ketones

ketonesaldehydes

esters

esters

Carboxylic acids

BOILING POINTS

VAPOUR PRESSURE

Stronger forces = highest boiling points, because more energy is neede to break the bonds

Increases with sizeBecause van der Waals forces increases with size, therefore longer chains have stronger forces and need more energy to break the bonds

Decreases with brancing, because branched chains cannot fit tightly together, therefore they are further apart and the van dier Waals forces weaker. Less energy is neede tot break the bonds

(how easily it evapourates) Decrease with size, because van der Waals force increase with sizeLong chaings have stonger forces, therefore more energy is needed to break the bonds and so longer chains take longer to evapourate

MELTING POINTSStronger forces = highest boiling points, because more energy is neede to break the bonds

Increases with sizeBecause van der Waals forces increases with size, therefore longer chains have stronger forces and need more energy to break the bonds

Increases with simmetry (of spherical shapes), because symmetrical molecules have a small surface area, meaning they can be packed close together and intermolecular forces are stronger…more energy is needed to to break the molecules from the solid network structure

SOLUBILITY“Like dissolves like”

THEREFOREIf the intermolecular forces between the solvent and

solute are the same, it will dissolveIt the forces are different, it will not dissolve

VISCOSITYResistance to flow (how sticky it is)Increases with size, because van der Waals forces increase with sizeLong chains have stronger forces and will therefore have a high viscosityDie teenstand teen vloei ( of hoe taai dit is)

Which one of the following compounds will have the highes boiling points?

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.

Which one of the following compounds will have the highes boiling points?

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.

The boiling points of branched alkanes are lower than their corresponding straight chain isomers,

because branched alkane chains have...

Greater Shorter More Smalle

molecular chain lenghts electrons

masses

A B C D r surface areas

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.

Which chemical properties of alkanes and alcohols make them suitable to be used as fuels

The table shows the boiling points of the first six alkanes an

a

b

d the first six alcohols

What trend in boiling po

int can be observed from the graph?

Provide a reason for the trend mentioned in by referring to the type of

intermolecular forces

Explain, referring to the type of intermolecular forces, why th

c

e e boi

b

ling points of alcohols are

higher than the boiling points of alkanes.

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.

a Alkanes & alcohols have low boiling points & combust easily

b Boiling points increase with chain lenght

c Van der Waals forces increase with molar mass

e Alcohols forms hydrogen bonds that are stronger than van der

Waals forces of alkanes. More energy is needed to break the bonds

between alcohols, therefore their boiling points are higher

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.

2 4 2

There exists two structural isomers for the organic

compound with molecular formula C H O

a Define th

rite down the structural formula of these two

is

e t

ome

erm structural

rs and next to 

isomer

b W

each it

s IUPAC name.

State with reason which ONE of these isomers

Has the higher boiling point

Has the higher vapour pressure

Will the vapour pressure of carboxylic acids

increase or decrease if the numb

c

d

e

er of carbon

atoms in the chain increases? Give a reason for your answer

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.

a theory

b .methyl methanoate etanoic acid

c Boiling points of carboxylic acids are higher that esters' because hydrogen bonds are

stronger that van der Waals forces and needs more energy to be broken

d The vapour pressure of esters are higher than carboxylic acids, because van der Waals

forces are weaker than hydrogen bonds and needs less energy to be broken. Therefore

esters will evapourate faster than car

vapour pressure decreases with size, because van der Waals forces increases with size

Long chains have stronger forces and needs mo

boxylic

re energ

acid

y to

s

e decrea

be br

se

oken

QUESTIONS ABOUT BOILING POINTS, SOLUBILITY, VISCOSITY etc.