Potential energy and Newman projections
Draw a diagram to show the changes in potential energy that occur from the rotation around the C1-C2 bond of 1-bromopropane. Draw Newman projection formulae to correspond with each maximum and minimum.
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Because of the free rotation about the C-C bond, 1-bromopropane exists in many conformations (conformers).
Drawing Conformations
There are three common ways of drawing conformations:
1] Wedges
2] Newman Projections
3] Sawhorse Structures
The most common Newman Projections are as below.
Newman Projections
The molecule is drawn as if it is viewed straight down the C-C bond.
Figure
The front carbon is drawn with 3 bonds in a Y shape
The back carbon is drawn as a circle (O) with 3 bonds pointing out from it.
1-bromopropane can adopt four important conformations.
1] Totally Eclipsed (A)
2] Gauche (B)
3] Partially Eclipsed (C)
4] Anti (D)
Now  represents the angle between the C-CH3 ...