Table 3.5  Energy Costs for Interactions in Alkane Conformers
		Energy cost
Interaction	Cause	(kJ/mol)	(kcal/mol)
H↔H eclipsed	Torsional strain	4.0	1.0
H↔CH3 eclipsed	Mostly torsional strain	6.0	1.4
CH3↔CH3 eclipsed	Torsional and steric strain	11	2.6
CH3↔CH3 gauche	Steric strain	3.8	0.9