Organic Chemistry
• Crude oil is a finite resource found in rocks
(it will run out)
• Crude oil is the remains of an ancient
biomass consisting mainly of plankton that
was buried in mud
Why is it so important to us?
Crude oil is a mixture of different
compounds called hydrocarbons.
A hydrocarbon is a compound
made of carbon and hydrogen
atoms only.
The hydrocarbons in crude oil are
mostly alkanes.
• General formula
• Complete questions 1-4
Different hydrocarbons have
different physical properties
depending on the length of
the chain
Short chain
Low
Boiling point
Viscosity (how Low (so very
thick it is)
runny)
Flammability High
(how easy it is
to set on fire)
Long chain
High
High (so very
thick)
Low
Complete questions 5-10
Boiling points and
separation
Complete question 11-26
Fractional distillation
Cool at the top
Molecules
rise up and
cool down
Crude
oil
Heated up
so all
different
alkanes
turn into a
gas
Condense
into a liquid
at their
boiling
point
Hot at the bottom
A mixture of:
A = boiling point of -42°C
B = boiling point of 125°C
C = boiling point of 380°C
50°C
Cool at the top
125°C
350°C
Hot at the bottom
Combustion
• Combustion reactions are when a
hydrocarbon reacts with oxygen
• Complete combustion always produces
carbon dioxide and water
• The reaction releases energy which can be
used
E.g. complete combustion
of methane
• Word equation
• Symbol equation
• Note that carbon and hydrogen have
been oxidised (had oxygen added to
them)
Incomplete combustion
• Incomplete combustion occurs when there
is not enough oxygen
• Incomplete combustion produces carbon
monoxide (which is a toxic gas)
• Methane and ethane example
Cracking
• There are long hydrocarbons and short ones
• The shorter ones are more useful
• Used as fuels and to help make polymers and other
useful chemicals
• Cracking turns the long ones into shorter ones
• One way is to pass over a hot catalyst
• Another way is to mix with steam and heat to a
high temperature
• Produce shorter alkanes and alkenes
• Alkenes are useful substances that are more
reactive than alkanes
Demo
Balancing equations
showing cracking
• C10H22  C5H12 + C3H6 + C2H4
• C10H22  C4H8 + C3H6
• Test for unsaturation
• Answer questions 37-46
Further organic (triple only)
Alkenes Triple only
• Double bond
• Unsaturation
• First four
• Questions 1 - 3
• Start reading page 158-159
Reactions of alkenes
• Combustion
• Same as alkanes but more often incomplete combustion
• Smoky flame
• Less energy
• Questions 4-6
• Read page 158-159
Reactions
• Additions with halogen
• Addition with hydrogen
• Addition with water (steam)
Alcohols
• Structure
• Functional group
• Homologous series
• Combustion
• Q9-14
• Start reading page 162-163
Alcohols with sodium
• Sodium + ethanol  sodium ethoxide + hydrogen
• 2Na + 2C2H5OH  2C2H5ONa + H2
• Questions 15-19
Alcohols in water
• Smaller alcohols dissolve readily in water
• Can be used as solvents
Alcohol with oxidising agent
• Turn into carboxylic acids
• Can occur naturally in the air
• Can be done in the lab
Alcohol formation
• Alkene with steam
• Fermentation of sugar
Carboxylic acids
• Formation from alcohols
• Notation for oxidising agent
• Reaction with carbonates
• Q20-27
Esters
• Formed from the reaction between an
alcohol and a carboxylic acid
• Sweet smelling, used in flavourings
• Only need to know ethyl ethanoate
• Q28-35