Question

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 would expect them to begin boiling

Answer 1

The expected boiling point of a substance increases with an increasing molar mass of the substance. So I would expect the lighter compounds to boil at lower temperature. Also more polar molecules tend to boil at higher temperature. Pentane is the lightest of all three compounds, so it should boil the soonest. Heptane is a lot heavier than Pentane, but slightly lighter than Heptanol. So it should boil next. Heptanol is the heaviest of all of the molecules and is also quite polar compared to heptane. So it should have the highest of all the boiling points.