Transcript Organic Chemistry

Organic Chemistry
10 Chemistry
Quiz
Alkanes
• General Formula
• Description
• Combustion
• Reactivity
• Chemical test
• Uses
• CnH2n+2
• Saturated
• Burns in Oxygen to
form CO2 + H20 (CO
with low O2)
• Low
• None
• Fuels
The chlorination of methane
• Halogenation is the replacement of one or
more hydrogens in an organic compound
by halogen atoms
• When methane is reacted with chlorine the
products of the reaction depend on
whether there is an excess of methane or
chlorine
• If there is an excess of methane it form
chloromethane and hydrogen chloride
To do
• Write down a word equation for the
chlorination of methane
• Can you write a chemical equation?
• How about a full balanced chemical
equation?
Movie
Halogenation
methane  chlorine  chloromethane  hydrogen chloride
CH 4  Cl2  CH 3Cl  HCl
CH 4 ( g )  Cl2 ( g )  CH 3Cl ( g )  HCl ( g )
With an excess of chlorine a mixture of products is formed. Chlorine can
obviously replace up to 4 of the hydrogen atoms.
Why halogenation?
• These products are generally used as
intermediate compound for further
synthesis
Natural Gas and Oil
Separating the fractions
Fractional distillation
• Preheated crude oil is pumped into the column
(340 C)
• The vapour in the crude oil rises due to
differences in density with different fractions
condensing in different regions
• The liquid part of the crude oil sinks in the
column
• The low density fractions are thin and light
coloured, the high density fractions are ‘viscous’
and dark
How does it work?
• Components separate due to different
boiling points
• Crude oil is a mixture of hydrocarbons
• Molecules are chemically bonded with
strong covalent bonds but contain different
numbers of carbon atoms
Go on…
• The weak attractive forces between the
molecules have to be broken if the
hydrocarbon is to boil
• The longer the hydrocarbon molecule is,
the stronger the intermolecular forces are
• The shorter chains are more volatile –
they form a vapour
Boiling
Volatility
• We can smell petrol (gasoline) much
easier than we can smell engine oil
• This is because petrol has 5-10 carbon
atoms and engine oil has 14-20 carbons
atoms
Combustion
combustion
Viscosity
Viscosity
Homework
• Go to: http://www.rscoilstrike.org/preloader.swf
• Play the game
• Take a screen shot (print screen) or use
the snipping tool to take an A4 image
• Print this out and stick it in
• Winner (most money) gets a ‘get out of
homework free’ card
Incomplete Combustion
Alkanes
The end of year test
• Can contain ANYTHING we have covered
over the course of this year (see specific
learning objectives)
• May contain anything from the Organic
Chemistry too
Origami time
Youtube
Homologous series
• A family of hydrocarbons is a homologous
series
• This means they have the same functional
groups
• You can have alcohols (ROH), alkanes (RH), Haloalkanes (RX) and MANY
OTHERS
Roger
Frost
Isomerism
• Hydrocarbons are based upon the number
of carbon atoms
• The carbon atoms can be rearranged in
different ways: these are called isomers
Alkenes
Alkenes
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•
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•
Formed from cracking
One or more double carbon bond
Hence unsaturated
Reactivity due to double bond
Tested with bromine water
Alkenes
Alkenes
• General Formula
• Description
• Combustion
• Reactivity
• Chemical test
• Uses
• CnH2n
• unsaturated
• Burns in Oxygen to form
CO2 + H20 (CO with low
O 2)
• High (double bond),
undergo addition
reactions
• Turns bromine water from
brown to colourless
• Making polymers
Isomers of Alkenes
Questions
• Q1 (a) Draw displayed formulae for
hexene
• (b) Describe a test to distinguish between
hexane and hexene
• Q2 Draw two isomers of pentene
• Homework: revise
Next lesson
• Oil spill clean up