Hey people! This article is just a little information on what i know about hydrocarbons. First of all the definition of a hydrocarbon. An organic compound only consistinf of only carbon and hydrogen atoms. In this article i will be briefly running over some things you must watch out for a things you need to know about hydrocarbons to continue onto later organic chemistry study. First of all ill be going over 2 things in this basic tutorial.

Functional Groups

a functional group is a group of atoms within a molecule that are responsible for the chemical reactions of those molecules.

The functional groups i will go over are alkanes, alkenes and alkynes.

although alkanes don’t have a functional group i have added it to remove confusion.

Alkanes

alkanes are determined by the suffix ‘ane’. The formula to figure out how many carbons and hydrogens in an alkane is CnH2n+2 so a propane molecule will be C3H8 you can tell the number ‘n’ because of the prefix of the molecule name. I remember them by a simple say

Rhyme/Prefix/# of carbons in the longest carbon chain in a molecule

My – Meth – 1 Carbon

Ex – Eth    - 2 Carbons

Partner – Pro – 3 Carbons

Breaks – But – 4 Carbons

Peoples – Pent – 5 Carbons

Hearts – Hex – 6 Carbons

this little saying can help you remember the starting of each prefix. My Ex Partner Breaks Peoples Hearts, you only need to remember up to about 10 carbons in a chain so for the purpose of study the next 4 are

Hept – 7 Carbons

Oct – 8 Carbons

Non – 9 Carbons

Dec – 10 Carbons

Alkanes aren’t put under any functional group so if you are asked what functional group alkanes are in the valid answer would be ‘None’. By carbons atoms in the longest carbon chain it means that later on in organic chemistry you are presented with bigger more complex hydrocarbons which can appear to be one prefix but when more closely examined can be another. This is when branch chains are introduced but i will not be going over these in this article

every carbon is always bonded 4 times whether it be to another carbon or a hydrogen. A basic alkane would be drawn as below.

The ‘H’s represent hydrogen and the ‘C’srepresent Carbon. The lines between the atoms represent a bond. Hydrogen atoms can only bond once due to the fact that they only have one valence electron. That covers alkanes.

Alkenes

alkenes are the same as alkanesbut they have a double bond where one of the carbon bonds would usually be. This makes the formula CnH2n. So a Butene molecule would have the formula of C4H8. The functional group of the alkenes is a ‘double bond’ this is what distinguishes them from other hydrocarbons. a diagram of a butene would be as below

Take note of how there is a double bondin the first bond and that the 2nd carbon and 1st carbon have one less carbon as a normal alkanebecause the double bond takes up 2 of the bonds each of the 1st and 2nd carbon have to offer. the name of this molecule would be but-1-ene but we will go over why that is in isomers.

Alkynes

An alkyne is another functional group that is represented by a triple bond in between a carbon this formula can be worked out by CnH2n-2. So a Butyne molecule would be C4H6. a Butyne molecule is shown below

as you can see the place of the triple bond is placed in between the prefix and the suffix, this is also done in the alkene group.

So that is a few functional groups in a nutshell

Isomers

An isomer is like a synonym but with molecules, the definition is a molecule with the same molecular formula but with a different structural formula. for example the double bond may be in a different place or it may include branch chains of carbons which can only be seen by a diagram ( branch chains may appear in another article i write. ) so an example of an isomer is shown below

The top Molecule would be a but-1-ene andthe second one would be referred to as a but-2-ene. This is because the double bond is in a different place. Isomers can be tricky to see when a diagram is presented to you. These become more difficult when branch chains are introduced.

So there you have it a very basic description of hydrocarbons this includes some information that may be handy to some people and will help if your struggling on the basic concept of hydrocarbons.

Thanks for reading