Conformational Isomerism: Rotations that Change Everything

The video tutorial explains conformational isomerism, focusing on ethane's carbon-carbon Sigma bond rotation. It describes the conditions for conformational isomerism, such as the presence of three continuous Sigma bonds. Ethane's free rotation at room temperature is discussed, along with the energy required for this rotation. The tutorial covers the formation of conformational isomers due to spatial arrangement changes in hydrogen atoms. It explains eclipsed and staggered conformations, highlighting the dihedral angle's role in these conformations.

What is required for a molecule to exhibit conformational isomerism?

• At least two pi bonds

• At least two continuous sigma bonds

• At least three continuous sigma bonds

• At least one pi bond

How much energy is needed for the carbon-carbon sigma bond in ethane to rotate?

• 3 kilojoules per mole

• 20 kilojoules per mole

• 5 kilojoules per mole

• 10 kilojoules per mole

What happens to the hydrogen atoms in ethane during carbon-carbon bond rotation?

• They remain in the same position

• They break away from the molecule

• They align differently with respect to each other

• They form new bonds

In an eclipsed conformation, how are the bonds on the front carbon aligned with the bonds on the back carbon?

• They eclipse or align with each other

• They are at a 45-degree angle

• They are perpendicular

• They are parallel

What is the dihedral angle in a staggered conformation of ethane?

• 90 degrees

• 60 degrees

• 30 degrees

• 0 degrees

How does the dihedral angle change when the front carbon is rotated by 60 degrees in an eclipsed conformation?

• It becomes 120 degrees

• It becomes 0 degrees

• It becomes 60 degrees

• It becomes 180 degrees

What is the dihedral angle in an eclipsed conformation of ethane?

• 90 degrees

• 60 degrees

• 30 degrees

• 0 degrees