Do you like organisms? How about chemistry?

Well that was our lamest title ever. Anyways, as you may have guessed, this post's topic is on Organic Chemistry. What is organic chemistry you may ask? Why it's the branch of chemistry that deals with substances containing a common element called Carbon. Carbon is everywhere. It's in the air, in your clothes, your food, medicine, furniture and so on. In fact, nearly one fifth of the human body is carbon.

The special thing about Carbon bonds is that they go more that one way. Sometimes it's straight, while other times it gets together with other carbons to link into a circle. It will even creates branches from a main line of carbons. See below for examples.

 

Straight

Circular

Branched

Hydrocarbons

Today we'll be focusing on a specific group of organic compounds, hydrocarbons. And even more specifically, we will be discussing alkanes and alkyls. Let's start off with alkanes.

Alkanes are a straight, single-bonded chain of carbons with hydrogens.

They are saturated (atoms can't bond to the alkane)

They end in "-ane"

Get it? Well you shouldn't, because we just told you some meaningless definitions and properties. Let's try something a little less abstract. 

This is Propane. As you can see, three carbon atoms are connected in a straight line with Hydrogens filling in the octets. Why is it called propane? IT JUST IS DEAL WITH IT. You'll want to memorize the prefixes for these alkanes. Not too hard. 

The alkanes are a homologous series. They follow a general pattern, in this case, it's C_nH_2n+2. And if you're wondering about what C₁₁H₂₄ is, it's Undecane. "Un" as in 1, and "dec" as in 10. Know your greek prefixes, kids!





Let's move on the alkyls. As you should already know, Carbon can bond with carbon. This gets interesting when hydrocarbons branch off from an alkane, like 2,2-dimethylhexane to the left there. How do we name these complex-looking substances? Well keep readings.

Find the longest chain of carbons. These aren't always in a horizontal line! They can make turns. The important part is finding the longest chain of carbons and the corresponding alkane. In the image to the left, it's a hexane. Cool, we figured out half of the name.

Second, start counting at one end of the chain, and find where it branches off with another carbon. You'll want to count from the end that gives a smaller number to the carbon where it branches off. Again, in the above image, this is the second carbon, so we know the numerical prefixes, 2. Now, what kind of alkyl branches off from there? It's actually very similar to alkanes, except the -ane is replaced with -yl. CH₃ is methyl, C₂H₅ is ethyl and so on. The general form for alkyls is C_nH_2n+1.

Third, find how many of that alkyl there is and add on a prefix. In this case, 2, so dimethyl.

And for this, we're finished with 2,2-dimethylhexane.

Of course, there are more complex substances like multiple branches and different alkyls, but this post is getting long already. You can probably figure it out yourself. Though here's an incomplete example. 2 methyls branch from carbon 3, and one ethyl from carbon 4 on heptane. It'll be 3-ethyl-2,2-dimethylheptane. Alphabetization and all that. If you don't understand all this text stuff, here's a video you lazy student.



Good luck with the test on the 24^th!