One measure of the amount of water in the atmosphere is the dew point, the temperature at which the atmosphere's water content would be in equilibrium with liquid water and droplets of dew would begin to form.

(a) On a warm summer day when the dew-point temperature is 68 °F, what is the pressure of water in the atmosphere? Refer to Figure 17-35 and note that the pressure of the water vapor (called the partial pressure of water) is equal to the vapor pressure at the dew-point temperature.

(b) If the weather changes and the partial pressure of water is reduced to 1.7 kPa, what is the new dew-point temperature?

Transcribed Image Text:

Vapor-pressure curve Liquid 4 Gas 10 20 30 40 Temperature (°C) 3. 2. Vapor pressure of water (kPa)