Hydrocarbons & Energy
Also Known As…
The Stuff That
Burns Real Fast
& Easy
What is a “hydrocarbon”?
Hydrocarbons are organic molecules that only contain carbon
and hydrogen atoms.
Organic molecules are made of carbon (and usually hydrogen),
they have energy, and are associated with living things.
Carbon is the key element in all organic compounds – especially
the hydrocarbons. It forms the skeleton for all hydrocarbons –
look at butane below – the carbons are the blue balls in the
diagram that make up the “spine” of the structure.
Types of Hydrocarbons
1.
2.
3.
Hydrocarbons are also known as aliphatic compounds
– organic compounds that can be straight, linear chains
or cyclical rings.
There are three main categories of hydrocarbons within
these linear and cyclic molecules…
Alkanes – hydrocarbons that have only single bonds
within the carbon chain.
Alkenes – hydrocarbons that have at least one double
bond within the carbon chain.
Alkynes – hydrocarbons that have at least one triple
bond within the carbon chain.
An easy way to remember this is the “A-E-Y” rule – they
go alphabetically and numerically with respect to the
bonds found between the carbons.
Naming Hydrocarbons
Hydrocarbons are just like us – they have a first
and last name. These names are great because
they actually describe the structure of the
molecule.
The first name indicates the number of carbons
in the chain of carbons that makes up the
hydrocarbon. This has to be the longest carbon
chain possible within the structure.
The second name tells you the category of
hydrocarbon – alkane, alkene or alkyne?
First Names of Hydrocarbons
The first name (or “prefix” if you are an English teacher) tells
you how many carbons are in the longest chain.
Meth = 1
Hex = 6
Eth = 2
Hept = 7
Prop = 3
Oct = 8
But = 4
Non = 9
Pent = 5
Dec = 10
This means that propane will have 3 carbons in its structure
and that heptane will have 7 carbons in its structure.
The first four are tough…I used to think…”ME & ETHyl went
in a PROP plane and it was BUTiful”. That’s awesome – I
came up with that all by myself too - I must be some sort of
Jenius!!!
If you just picked on me for spelling genius incorrectly – you
are the real jenius for missing the obvious sarcasm…nice
job Einstein!
The Last Name
The last name (or “suffix”) tells you the type of
hydrocarbon you have.
If the name ends in…



ANE – it is an alkane – all single bonds between the
carbon.
ENE – it is an alkene – at least one double bond in
the carbon chain.
YNE – it is an alkyne – at least one triple bond in the
carbon chain.
This means that pentane, pentene and pentyne
all have five carbons but pentane is all single
bonds, pentene has at least one double bond
and pentyne has at least one triple bond in the
carbon chain somewhere…But where???
The Numbers Game
Some hydrocarbons will have numbers in their
name. These numbers tell you the position of special
bond types or side groups that can be found on or
within the larger carbon chain.
Please note – chemists are LAZY!!! They will always
count from the end of the chain that will give them
the lowest possible number combinations.
You can start counting carbons from either end of the
carbon chain to make it easier for you.
This means that the carbon that starts off a double or
triple bond, or a functional group, will be numbered
to tell its position along the chain.
Lazy! Lazy! Lazy! First the “e” on the end of mole
and then this…What will they do next?!?!?!
Allow Myself To Introduce…Myself…
Now…lets use all of the names and
numbers together…
Name the following hydrocarbons!
THE END