Question

How do boiling points change at high altitudes?

Answer 1

When we talk about a high altitude, we consider $3000{\text{ }}feet$ above sea level to be high altitude. At $2000{\text{ }}feet$ above sea level, the boiling temperature of water is $208{\text{ }}F$ instead of $212{\text{ }}F$. We know that at higher altitudes, the substance boils faster than at sea level. This means that the boiling points are lower.

Complete step-by-step answer:
Above$2500{\text{ }}feet$, the atmosphere becomes much drier. The air has less oxygen and atmospheric pressure, so cooking takes longer. Moisture quickly evaporates from everything.

At high altitudes, the atmospheric pressure is lower. This means that when a substance boils, this would mean that the vapour pressure which is of the substance must be equal to the pressure of the surrounding.

Now as we know, the atmospheric pressure at sea level is $1{\text{ }}atm$, this means than when a substance gets hot enough and then when its vapour pressure reaches $1{\text{ }}atm$, the process of boiling starts.

At high altitudes, the vapour pressure is comparatively lower than that at sea level, thus the vapour pressure of the substance matches the atmospheric pressure quicker than it would at a lower altitude. This would mean that when the altitude increases, the boiling point decreases.

Note: When it comes to comparison, the atmospheric pressure at the top of Mount Everest is $0.36{\text{ }}atm$. This means that if anyone plans to boil water at the top of Mount Everest, it is more likely to boil faster at that altitude. Thus we can state that the boiling point is the temperature at which the vapour pressure of that substance equals the atmospheric pressure.