Naming Alkanes

Hey guys! In this new video, we're going to continue with our discussion of naming alkanes. In this first one, we’re asked to name the following alkane compound. What we need to realize here is that here we have a ring. This is a cyclic alkane. Because it's in a ring, we say cyclo. Here it has six carbons because remember every edge, every corner is a carbon. There’s six carbons within this ring. It's going to be called cyclo because it's cyclic. Six carbons is hexane. This is a cyclohexane.
You want to number the carbons in the ring in a way that these groups which are substituents which didn't get numbered get the lowest numbers possible. What does that mean? That means that I want to count either one, two, three or one, two, three. Here it really doesn't matter because it's symmetrical both ways. Let's go with the first way. We're going to stay here that this is one carbon, a CH3, so this is a methyl.
Again, it becomes important that you guys remember what these groups look like. Here this is three carbons connected to something, so this is a propyl. Again, this is a methyl. M before p so alphabetical order for substituents. There are two methyls so that's dimethyl. They're located on carbons 1 and 3. This would be 1,3-dimethyl and notice how the numbers are grouped together and separated by a comma but numbers and words are separated by a hyphen. Then the propyl is on carbon 2 so hyphen, because that propyl is on carbon 2. 2-propyl cyclohexane. That should all be one word, so I'm going to move it closer. That would be the name of our compound. Again, because we're dealing with a ring, we use the word cyclo now.
Now that we've attempted this one, take a look at the next one. Once you figure out what it could possibly be named, click on the next video and see an example of me going over it and see if your answer matches mine.

Alright guys! Let's continue with the naming of alkanes. Here in this next example, we’ve got to name this structure. What we got to do here is look for the longest chain. You can go one, two, three. You can go one, two, three. You can go one, two, three. It doesn't matter which way you count. The longest chain is three carbons. Let's just make it simple on ourselves. We’ll say that this is the longest chain, which means these two things here are substituents. That's a methyl here and a methyl here. We want to count from the end, one of the end. We can say 1, 2, 3 or 1, 2, 3 the other way. We count from the end closest to the substituents. Either way it gets me there on carbon 2.
Here's the thing. There's two methyl so that's dimethyl. I know they’re both on the same carbon but you can't say 2 dimethyl because to dimethyl means this. 2-dimethyl just means, okay there are two methyl groups and I know the location of one of them. One of them is on carbon 2 but I don't know what the location of the other one is. You have to actually say 2,2-dimethyl. You have this state 2 twice because each one is its own separate thing located on carbon 2. We use di to pull them together because they have similar names. But each one is it's an individual substituent. We have 2,2-dimethyl and a three-carbon chain is propane. That's what we’ll name this structure.
Keep practicing. Keep going all over all the different examples that we’re going through. Attempt to do the next one. Click on the next video and see how I answer it. Check to see if your answer matches mine.