The energy difference between the Chair conformations with simple alkyl group at  equatorial position and  at axial position  is _____ 

The two chair conformation Cyclohexane the axial and the equatorial position, interconvert at room temperature, so that one has lower energy predominantly, careful  measurements have shown that the Chair with  equatorial position of groups  is the most stable conformation. It is about 7.6KJ/mole approx.