Atmospheric pressure decreases as altitude increases. In other words, there is 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 (C7H15OH) are heated evenly at different altitudes, rank them according to the order in which you expect them to begin boiling. Rank from first to last. to rank as equivalent, overlap them.