Newman projections 2 | Organic chemistry | Khan Academy

TL;DR

This video demonstrates how to visualize the structure of the butane molecule using a Newman Projection.

Transcript

In the last video, we visualized an ethane molecule with a Newman Projection. What I want to do in this video is show that you can really visualize longer chains, or even, we'll see in future videos, even cyclical, ring-based carbon molecules with Newman Projections as well. And I guess the next most complex molecule to study would be butane. We co... Read More

Key Insights

• 😋 Newman Projections can be used to visualize the structure of organic molecules, including longer carbon chains and cyclical ring-based molecules.
• ❓ Butane, a molecule with four carbons, is an example used to demonstrate the visualization process.
• 🧑‍🌾 The most stable conformation of butane is the anti-conformation, where the methyl groups are as far apart from each other as possible.
• 🧑‍🌾 The Gauche conformation occurs when the methyl groups are staggered but not as far apart as in the anti-conformation.
• 👥 The eclipsed conformation, with methyl groups directly behind each other, is the least stable conformation.
• 🧘 Different conformations of a molecule can be achieved by rotating the carbons and observing the positions of the attached groups.
• 😘 The potential energy of a molecule is lower in more stable conformations.

Questions & Answers

Q: How do you create a Newman Projection for a butane molecule?

To create a Newman Projection for a butane molecule, choose two carbons as the front and back, and represent the rest of the molecule as a group. Then, draw the front carbon with the attached groups, and the back carbon with the attached groups, showing the relative positions of the atoms.

Q: What is the most stable conformation of a butane molecule?

The most stable conformation of a butane molecule is known as the anti-conformation. In this conformation, the methyl groups are as far apart from each other as possible, resulting in the lowest potential energy.

Q: What is the Gauche conformation in a butane molecule?

The Gauche conformation is a slightly less stable conformation in a butane molecule where the methyl groups are staggered but not as far apart from each other as in the anti-conformation. This conformation occurs when the molecule is rotated slightly from the anti-conformation.

Q: What is the eclipsed conformation in a butane molecule?

The eclipsed conformation is the least stable conformation in a butane molecule. In this conformation, the methyl groups are directly behind each other, resulting in a higher potential energy.

Summary & Key Takeaways

• The video explains how to visualize longer carbon chains, including cyclical ring-based carbon molecules, using Newman Projections.

• Butane, a molecule with four carbons, is used as an example to demonstrate the visualization process.

• By choosing two carbons as the front and back, and representing the rest of the molecule as a group, a Newman Projection can be created to visualize different conformations.