about Isopantane conformation, say, most top as 0 degree, then is the most stable conformation, CH3 at 0 and 120 degree, and H at 240d. Then other side has H at 60, 300d, CH3 at 180d? also, Is the 2nd most stable conformation, CH3 at 0,120d, H at 240, then on the other side has H at 0, 120, CH3 at 240d?? and is this a gauche conformation?