Atmospheric pressure decreases as altitude increases. In other words, there are more air pushing down on you at sea level, and there is less air pressure pushing down on you when you are on a mountain. If pentane (C5H12), heptane (C7H16), and heptanol (C7H15OH0 are heated evenly at different altitudes, rank them according to the order in which you would expect them to begin boiling. rank from first to last. To rank items as equivalent, overlap them.