Question

On a mountaintop, it is observed that water boils at 90°C, not at 100°C as at sea level. This phenomenon occurs because on the mountaintop the...

(A) equilibrium water vapor pressure is higher due to the higher atmospheric pressure
(B) equilibrium water vapor pressure is lower due to the higher atmospheric pressure
(C) equilibrium water vapor pressure equals the atmospheric pressure at a lower temperature
(D) water molecules have a higher average kinetic energy due to the lower atmospheric pressure
(E) water contains a greater concentration of dissolved gas

Answer 1

On a mountaintop, water boils at a lower temperature because the equilibrium water vapor pressure equals the atmospheric pressure at a lower temperature. As a result, the boiling point of water is reduced from 100°C at sea level to 90°C.

Step-by-step explanation:

The boiling point of water is affected by external pressure. At higher altitudes, the atmospheric pressure is lower, which leads to a lower boiling point. For example, on a mountaintop, water boils at 90°C instead of 100°C at sea level. This occurs because the equilibrium water vapor pressure equals the atmospheric pressure at a lower temperature.