Draw potential energy vs dihedral angle graph for conformational analysis of propane as it rotates around the single bond between C1 and C2. Also, draw the Newman projections for each eclipsed and staggered conformation and show the dihedral angles.

Hint: One C—H bond eclipsed with another C—H bond contributes to 4.2 KJ/mol torsional energy. One C—H bond eclipsed with a C—CH₃ bond contributes to 5.4 KJ/mol torsional energy.