Organic chemistry naming examples 3 | Organic chemistry | Khan Academy

TL;DR

Learn how to name complex molecular structures in organic chemistry, including identifying the longest chain and determining the order of side chains in the name.

Transcript

We've got a few more molecular structures to name, so let's look at this first one right here. The first thing you always want to do is identify the longest chain. If we start over here, we have one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen carbons, looks pretty long. Now what if we start over here? This looks ... Read More

Key Insights

• 🪘 The longest chain in a molecular structure is crucial for determining the compound's name.
• 👥 If two chains have equal length, choose the one with more alkyl groups.
• ⛓️ Count the carbons in the main chain, starting from the side with the first branch.

Questions & Answers

Q: How do you determine the longest chain in a molecular structure?

To identify the longest chain, count the number of carbons in each potential chain and choose the chain with the most carbons.

Q: What should you consider when deciding between two equal-length chains?

In the case of two equal-length chains, choose the chain that has more alkyl groups or branches on it.

Q: How do you count the carbons in the main chain?

Start counting from the side where you encounter the first branch and count each carbon along the chain until you reach the end.

Q: How should you name side chains when there are multiple branches?

Order the side chains alphabetically and number them according to their alphabetical order. Use prefixes like methyl, propyl, etc., to indicate the number of carbons in each side chain.

Summary & Key Takeaways

• In organic chemistry, the longest chain in a structure should be identified first, and if there are two equal-length chains, choose the one with more alkyl groups.

• Count the carbons in the main chain, starting from the side where you encounter the first branch, and name it according to the number of carbons (tridec- for thirteen carbons).

• Use alphabetical order to list the side chains (methyl and propyl) and number them according to their alphabetical order.