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LUCIA ROMERO

14
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1 NAMES OF COMPOUNDS
Hydrocarbons
→ A compound that contains only hydrogen and carbon atoms (e
...
, alkanes, alkenes but NOT alcohols or carboxylic acids)
COMBUSTION OF HYDROCARBONS
→ These compounds undergo complete and incomplete combustion
1
...


Incomplete combustion

When does it occur? When there is insufficient oxygen to burn
What are the products? Either carbon monoxide and water OR carbon and water form
: 2CH4+ 3O2→ 2CO + 4H2O
: CH4+ O2→ C + 2H2O
How to name organic compounds
The prefix: tells you how many carbon atoms are present in the longest continuous chain in the compound
The suffix: tells you what functional group is on the compound
EXAMPLES
Methane

Ethene

Propanol

Butanoic acid

- prefix: 1 carbon atom

- prefix: 2 carbon atoms

- prefix: 3 carbon atoms

- prefix: 4 carbon atoms

- suffix: ane = alkane

- suffix: ene = alkene

- suffix: anol = alcohol

- suffix: anoic acid = carboxylic acid

Pentamine

- prefix: 5 carbon atoms
- suffix: amine = amine
NAMING ESTERS
Esters are formed when
...

- the name of the ALCOHOL goes FIRST, getting rid of the -anol and adding -yl
- the name of the CARBOXYLIC ACID goes SECOND, getting rid of the -oic acid and adding -oate
Example:
Ethanoic acid + propanol → propyl ethanoate
Methanol + butanoic acid → methyl butanoate
-

(however, when drawing the structure of an ester, the carboxylic acid comes first)

14
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coal

2
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petroleum (crude oil: found under porous rock under the ground & under the sea)(refining process before use, not other FF)

LUCIA ROMERO
Refining of petroleum

•

Petroleum itself as a mixture isn’t very useful but each component part of the mixture, called a fraction, is useful and each fraction has
different applications

How are the fractions of petroleum separated?
By fractional distillation in a fractionating tower

How?
The molecules in each fraction have similar properties and boiling points → depend on the number of carbon atoms in the chain
EXPLAINING THE PROCESS

➢

The fractionating column is hot at the bottom and cool at the top

1
...


Vapors of hydrocarbons with very high boiling points → immediately turn into liquid → tapped off at the bottom of the column

3
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- The fractions containing smaller hydrocarbons are collected at the top as gases (as they have the lowest boiling points and are the
most VOLATILE)
- The fractions containing bigger hydrocarbons are collected at the lower sections

PROPERTIES OF THE MAIN FRACTIONS OF CRUDE OIL
1
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: high viscosity liquids are thick and flow less easily
: if the number of carbon atoms increases, the attraction between the hydrocarbon molecules also increases which results in the
liquid becoming more viscous → with the increasing length of the hydrocarbon chain (the liquid flows less easily with increasing
molecular mass)

2
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1–4

i
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Gasoline

5-6

i
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Naphtha

6 - 10

i
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Kerosene (paraffin)

10 - 15

i
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Diesel (gas oil)

15 - 20

i
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Fuel oil

20 - 30

i
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Lubricating fraction

30 - 50

i
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Bitumen

50 - upwards

ii
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polishes

i
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covering roofs

LUCIA ROMERO

14
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The same general formula

2
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Similar chemical properties - due to them having the same functional group

DIFFERENCES BETWEEN MEMBERS IN A HOMOLOGOUS SERIES:
1
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Different physical properties – due to increasing molecular size

Structural isomers
WHAT ARE THEY?
Compounds with the SAME MOLECULAR FORMULA but a DIFFERENT STRUCTURAL FORMULA
- due to different arrangement of atoms in space
- the longer the carbon chain, the more structural isomers
EXAMPLES

Propan – 1 – ol

Propan – 2 – ol

(for the number in between start counting from the right to where the OH is)
ISOMERS & BOILING POINTS
➢

The compounds with branched chains have LOWER boiling points

WHY? Because the branches prevent the molecules from getting close together – attractive forces between them are weaker – less
energy needed to form a gas

14
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They are hydrocarbons

2
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General formula: CnH2n+2

4
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All are generally unreactive (except in terms of burning)

6
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COMBUSTION

Reactants

alkane + oxygen (incomplete combustion happens if there is not enough oxygen)

Other requirements

a flame to ignite the fuel

Products

carbon dioxide (would be carbon monoxide if it was incomplete combustion) + water + heat

Equation for methane

CH4 + 2O2 → CO2 + 2H2O

LUCIA ROMERO
2
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5 ALKENES
General characteristics
1
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There is a double covalent bond between two of the carbon
atoms

3
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Functional group: C=C

5
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Alkane → alkene + alkane

e
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, C10H22 → C7H14 + C3H8
2
...
g
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Alkane → 2 or more alkenes + hydrogen

e
...
, C10H22 → 2C5H10 + H2
CONDITIONS
1
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Aluminium oxide catalyst

Reactions of alkenes
1
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REACTION WITH WATER (CATALYTIC ADDITION OF STEAM)

Type of reaction → addition / hydration / reversible / exothermic
Product: alcohol

LUCIA ROMERO
Conditions:
1
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60-70 atmospheres

3
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REACTION WITH HYDROGEN

Type of reaction → addition / hydrogenation / reversible
Product: alkane
Conditions:
1
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Nickel catalyst

4
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g
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6 ALCOHOLS
General characteristics
1
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General formula: CnH2n+1OH

3
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All their carbon atoms form single bonds

5
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The most important alcohol is ethanol

Methods to obtain ethanol
1
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Sugar or starch is dissolved in water and yeast is added

2
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Yeast contains enzymes that break down starch or sugar to glucose
- If the temperature is too low the reaction rate will be too slow and if it is too high the enzymes will become denatured

4
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The yeast are killed off once the concentration of alcohol reaches around 15%, hence the reaction vessel is emptied and the process is
started again (this is the reason that ethanol production by fermentation is a batch process)

6
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HYDRATION OF ETHENE

(look at hydration of ethene in reactions of alkenes)
COMPARING THE TWO METHODS
= disadvantages
= advantages

Uses of ethanol
1
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As a fuel – burns readily in air giving out plenty of heat

14
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They are NOT hydrocarbons

2
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General formula: CnH2nO2

4
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The most common carboxylic acid is ethanoic acid
- Ethanoic acid is a typically weak acid and dissociates slightly in water, producing a mildly acidic solution
: The equilibrium lies far to the left during ionization:
CH3COOH ⇌ H+ + CH3COO-

6
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OXIDATION OF ETHANOL BY FERMENTATION

Type of reaction: acid fermentation

- to make vinegar from fruits and other foodstuffs
Process:
1
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Bacteria will bring about its oxidation to ethanoic acid
: C2H5OH + O2 → CH3COOH + H2O

2
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Concentrated sulfuric acid catalyst

Example to form propyl ethanoate using propanol and ethanoic acid:

What is the functional group in an ester? The ester linkage
- COO
What are esters used for? Flavorings and fragrances (as they
have distinct smells and flavors)
More examples of esters:

14
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8
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covalent bonds

2
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ester links

LUCIA ROMERO

14
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2 Synthetic polymers
TYPES OF SYNTHETIC POLYMERS
1
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Nylon: (a polyamide) used to make clothing, fabrics, nets and ropes

3
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8
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g

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