When are water vapor pressure and saturation vapor pressure the same?

ATMOSPHERE: 33. Water is said to boil when the saturation vapor pressure of the water equals the surrounding a?

• 33. Water is said to boil when the saturation vapor pressure of the water equals the surrounding air pressure. At sea level, water boils at a temperature of 100° C, which means that the saturation vapor pressure of liquid water at 100° C is equal to 1013 mb (sea level air pressure). Do you expect water will boil at a higher, lower, or the same temperature on top of a 10,000 ft mountain? You must explain the reason for your answer. (Hint. Consider the change in air pressure between sea level and the top of a mountain. You must also understand how the saturation vapor pressure of water changes with the water temperature).

• Answer:

  Water will boil at a lower temperature than 100 degrees C atop a 10,000 foot mountain because air pressure is less at altitudes higher than sea level.