Naming Alkanes - Online Tutor, Practice Problems & Exam Prep

In organic chemistry, alkanes are named using the IUPAC nomenclature system, which assigns names based on the number of carbon atoms. The prefixes for alkanes are: 1 carbon (meth-), 2 (eth-), 3 (prop-), 4 (but-), 5 (pent-), 6 (hex-), 7 (hept-), 8 (oct-), 9 (non-), and 10 (dec-), with all names ending in "-ane." Understanding these prefixes is essential for identifying and naming hydrocarbons, which are fundamental in organic chemistry.

Rules for Naming Alkanes Concept 1

In this video, we're going to take a look at naming alkanes. Now, in naming organic compounds, we use the IUPAC 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 alkanes, it'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 end 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; you could have 11, 12, 13. But for this level of chemistry, we work within our range of 1 to 10. For those of you who are going to go later on into Organic 1 and Organic 2, you go into larger chains where you're going to go beyond 10, depending on your professor's inclinations.

So here we're going to say if you have one carbon, then your prefix is "Meth". So a one carbon alkane will be called Methane. Remember, this is the prefix that ends with "ane". Two carbons, the prefix would be "Eth", so a 2 carbon alkane is Ethane. 3 would be "Prop", Propane. 4 would be "But", Butane. 5 carbons. Now here at this point, some of it makes sense because we know pentagram, 5 sides. We're going to say pentagon, 5 sides. So 5 is "Pent", Pentane. Hexagon, 6 is Hexane. 7 carbons is "Hept", Heptane. 8 carbans is "Oct", Octane. 9 carbons is "Non", so this is a little weird, Nonane. And then 10 carbons is "Dec", Decane. So some of these terms we know Decane, decathlon, we know it runs with it 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 alkanes.

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

Naming Alkanes Example 1

It says, name the following alkanes. All of them are alkanes because all of them are carbons 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 a number of carbons. For this first one, it's only 1 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 1, 2, 3, 4 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? 1, 2, 3, 4, 5, 6. 6 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.

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Here’s what students ask on this topic:

What is the IUPAC naming system for alkanes?

The IUPAC naming system for alkanes is a standardized method used to name organic compounds based on the number of carbon atoms in the molecule. The names of alkanes end with the suffix '-ane' and use specific prefixes to indicate the number of carbon atoms. For example, a one-carbon alkane is called methane, a two-carbon alkane is ethane, and so on. The prefixes are: 1 (meth-), 2 (eth-), 3 (prop-), 4 (but-), 5 (pent-), 6 (hex-), 7 (hept-), 8 (oct-), 9 (non-), and 10 (dec-). This system helps in systematically identifying and naming hydrocarbons, which is fundamental in organic chemistry.

How do you name an alkane with 5 carbon atoms?

An alkane with 5 carbon atoms is named using the prefix 'pent-' followed by the suffix '-ane'. Therefore, the name of a 5-carbon alkane is pentane. The prefix 'pent-' is derived from the Greek word for five, and the '-ane' suffix indicates that the compound is an alkane, which is a saturated hydrocarbon with single bonds between carbon atoms.

What are the prefixes for naming alkanes with 1 to 10 carbon atoms?

The prefixes for naming alkanes with 1 to 10 carbon atoms are as follows: 1 (meth-), 2 (eth-), 3 (prop-), 4 (but-), 5 (pent-), 6 (hex-), 7 (hept-), 8 (oct-), 9 (non-), and 10 (dec-). These prefixes are combined with the suffix '-ane' to form the names of the alkanes, such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane.

Why is it important to learn the IUPAC naming system for alkanes?

Learning the IUPAC naming system for alkanes is important because it provides a standardized and systematic way to name organic compounds. This system ensures that chemists around the world can communicate clearly and unambiguously about specific compounds. Understanding the IUPAC nomenclature helps in identifying the structure and properties of alkanes, which is essential for studying organic chemistry, conducting research, and working in various chemical industries.

What is the name of an alkane with 8 carbon atoms?

An alkane with 8 carbon atoms is named using the prefix 'oct-' followed by the suffix '-ane'. Therefore, the name of an 8-carbon alkane is octane. The prefix 'oct-' is derived from the Greek word for eight, and the '-ane' suffix indicates that the compound is an alkane, which is a saturated hydrocarbon with single bonds between carbon atoms.