First 224 words of the document:
Alkanes and Alkenes
There is often a lot of confusion between the two but the key
difference is that alkenes have a double bond and alkanes
The key point that has to be remembered is that the bigger
the hydrocarbon, the less reactive it is.
(In case you are wondering, a hydrocarbon is a molecule
made up of hydrogen and carbon atoms.)
Hydrocarbons come from crude oil, and it may not be the only
source, but it is the main one.
To get the different hydrocarbons you have to use a machine
which is called a fractional distillatory (or something like that!).
What happens is there is a huge amount of crude oil at the
bottom of the fractional chamber. Heat is passed through the
crude oil to make it into a vapour. Because different parts of
crude oil have different properties, then reactive fractions of
crude oil will rise to the top of the chamber where it is cool. To
make it easier, here is a diagram...
As you can see,
the vapour passes
column, and if it is
volatile then it
rises to the top,
where it is cool
Other pages in this set
Here's a taster:
Here is a list of all the alkanes...
o And so on...
The more volatile gases like methane and ethane are used in
petrol and cooking gas. However the heavier ones are used
for roads and fuel e.g. bitumen.…read more