Naming Alkanes - Online Tutor, Practice Problems & Exam Prep

Understanding the IUPAC nomenclature is essential for naming organic compounds, particularly alkanes. Alkanes are named based on the number of carbon atoms they contain, using specific prefixes that correspond to these numbers, followed by the suffix "-ane." For instance, an alkane with one carbon is called methane, two carbons is ethane, and this pattern continues up to decane for ten carbons. Recognizing these prefixes—meth, eth, prop, but, pent, hex, hept, oct, non, and dec—is crucial for identifying and naming alkanes correctly. This systematic approach lays the foundation for more complex organic chemistry studies, where chains can exceed ten carbons.

Rules for Naming Alkanes

In this video, we're going to take a look at naming alkanes. Now in Naming Organic Compounds we use the IU PACK method of nomenclature or naming system. IUPAC stands for the International Union of Pure and Applied Chemistry. This is just our systematic set of rules when it comes to naming different organic compounds.

Now starting with naming alkane, that's first important to remember our alkane prefixes. We're going to say alkane names are based on the number of carbons present in a molecule and end with ane alkanes and with ane. That's how it works. Now we use the following prefixes to name the base of the alkane. So if we take a look here at our alkane prefixes, it goes from 1 carbon all the way up to 10.

Now of course you can have a chain that has greater than 10, umm you could have 11/12/13. But for this level of chemistry we work within our range of one to 10. For those of you who are going to go later on into organic one, in organic two you go into larger chains where you're going to go beyond ten depending on your professors inclinations.

So here we're going to say if you have one carbon then your prefix is meth. So A1 carbon alkane will be called methane. Remember this is the prefix. The end with ane two carbons of prefix would be eth so A2 carbon alkane is ethane 3 would be prop propane four would be but butane 5 carbons. Now here at this point some of it makes sense because we know pentagram five sides, we're going to say Pentagon five sides. SO5IS pent.

Pentane hexagon 6 is hexane 7 carbons is hept. Heptane 8 carbons is octane 9 carbons is non. So this is a little weird, no name. And then 10 carbons is deck decane. So some of these terms we know decane decathlon we know rhymes with associates with the number of 10, right? So just remember these are our numerical prefixes or alkane prefixes. The endings of them would be ane because they represent alkane's.

Alright, So before we start into naming, it's important to recall these alkane prefixes.

Naming Alkanes Example

Here it says name the following alkanes. All of them are alkanes because all of them are carbon single bonded to one another. Now remember, since they're alkanes, their endings would be ane, and we'd say that their prefix is based on the number of carbons.

For this first one, it's only one carbon, and we know that the prefix would be meth. So the name of this alkane is methane. For the next one, how many carbons do we have? We have one 234 carbons. The prefix would be but so this is butane.

And then here we have it in its skeletal formula. So remember, each line connects 2 carbons together. So there's a carbon here, here, here, here, here and here. How many carbons is that? 123-456 would mean that our prefix is hex, so the name of this alkane will be hexane.

So just remember they're all alkane, so their endings are ane. And then you just have to remember what is your alkane prefix based on the number of carbons present. Putting those together gives us our alkane name.

Provide a skeletal structure for nonane.

• A.
• B.
• C.
• D.

Here’s what students ask on this topic:

What are the rules for naming alkanes?

Naming alkanes follows the IUPAC (International Union of Pure and Applied Chemistry) nomenclature system. Here's a simplified summary of the rules:

1. Identify the Longest Carbon Chain: This becomes the base name of the alkane. Count the number of carbons in the longest continuous chain to determine the prefix (meth- for 1 carbon, eth- for 2, prop- for 3, etc.), and add the suffix "-ane" to indicate that it's an alkane.
2. Number the Chain: Assign numbers to the carbon atoms in the main chain starting from the end nearest to the first branch or substituent. This ensures that the substituents get the lowest possible numbers.
3. Name and Number Substituents: Identify the alkyl groups (substituents) attached to the main chain and use a prefix to indicate the number of carbon atoms they contain. If there's more than one identical substituent, use prefixes like di-, tri-, tetra-, etc., to indicate how many there are.
4. Assemble the Name: Combine the names of the substituents with the base name of the alkane. List the substituents in alphabetical order, preceded by the number indicating the carbon to which they are attached. Use commas to separate numbers and hyphens.

Naming alkanes, what is the proper name of this compound?

To name an alkane, you need to follow the IUPAC (International Union of Pure and Applied Chemistry) nomenclature rules. Unfortunately, you haven't provided the specific structure of the compound you're asking about, so I can't give you the exact name. However, I can guide you through the general steps for naming an alkane:

1. Identify the longest continuous chain of carbon atoms; this will determine the base name of your alkane (methane, ethane, propane, etc.).
2. Number the carbon atoms in the longest chain starting from the end nearest to any substituent (branch or side chain).
3. Identify and name the substituents (alkyl groups) attached to the main chain.
4. Assign a number to each substituent according to its position on the main chain.
5. If there are multiple substituents of the same type, use prefixes such as di-, tri-, tetra-, etc., to indicate their quantity.
6. Arrange the substituents in alphabetical order when listing them in the compound's name.
7. Combine the elements of the name into a single word, with hyphens separating numbers from letters and commas separating numbers from each other.

For example, if you have a four-carbon chain with a methyl group on the second carbon, it would be named 2-methyl.