C7 - Organic Chemistry Flashcards
What is crude oil?
Crude oil is a mixture of a very large
number of compounds.
Most of the compounds in crude oil
are hydrocarbons, which are molecules
made up of hydrogen and carbon
atoms only
What is an alkane?
An alkane is a saturated hydrocarbon
molecule.
Saturated means that all the carbon bonds are single bonds. This means no more hydrogen atoms can be added
Name the first 4 alkanes and give
the general formula.
Methane
Ethane
Propane
Butane
CnH2n+2
Describe how the properties of
the alkanes are affected by the size
of the molecules.
As the molecules get bigger the
viscosity and boiling point increase.
As the molecules get bigger the
flammability decreases
How does fractional distillation
work?
Different hydrocarbons have different
boiling points.
The lower boiling points evaporate and
rise further up the fractionating
column.
They condense at different heights
and the liquids are collected
What is the general word equation
for burning hydrocarbon fuels?
Fuel + oxygen → carbon dioxide + water
What is the difference between complete and incomplete combustion?
Complete combustion is when there is
enough oxygen to form carbon dioxide and water.
Incomplete combustion is when there is not enough oxygen to form carbon
dioxide so some carbon monoxide and carbon particulates (soot) are formed
What is cracking?
Cracking is the process of breaking less useful longer chain hydrocarbons into
more useful shorter chains.
It can be done by using a hot catalyst
or by mixing with steam at a high
temperature
What is an alkene and what is
the general formula?
An Alkene is an unsaturated hydrocarbon.
This means it has a carbon double bond and can have more elements added to it.
CnH2n
How do you test a hydrocarbon to
determine if it is an alkane or alkene?
Add orange bromine water to the hydrocarbon.
Alkenes are more reactive. They turn
the orange bromine water colourless
