# Water can change from one phase to another, given the right condition.whay condition will allow water to evaporate?

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• 6 months ago

To go up in altitude, you reduce the pressure on the water, thus the boiling point goes down, down down, until you can actually boil water at room temperature!!!!.

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• 6 months ago

If you have a Dreschel bottle containing pure liquid water and head of the bottle having sintered end or fritted glass end then pass an inert gas through the bottle. Gas will absorb moisture and at equilibrium get saturated depending upon the vapor pressure at the temperature of liquid water bottle. By using a relative humidity sensor at the outlet of the bottle and the temperature at the location of that sensor, you can know when equilibrium has reached. At 298.15K, vapor pressure of pure water is 3169Pa. Keep the dreschel bottle having water in a cooling bath with temperature of 298.15K and start flowing the inert gas at lowest possible flowrate. Make sure that the height of utility fluid level of the bath is above the height of water inside the bottle and the tubing outside the bath is covered with heating ropes and thermal insulation to prevent condensation. After 7-8 hours, equilibrium will be reached and will be 3.17% at total pressure of 100kPa. Total pressure varies instantaneously at a given altitude. So molefraction of water vapor in the inert gas exiting the bottle will vary with total pressure variation.

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• 6 months ago

water evaporates ....

Liquid water will evaporate at zero Celsius, albeit a bit slower than at some elevated temperature. The evaporation of water is a spontaneous process (increases in entropy) and occurs at all temperatures where water is a liquid.

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• 6 months ago

a P-T condition where liquid is the thermodynamically stable phase for the compound. You need liquid to evaporate, and you cannot have liquid outside the range of stability. Of course, you also need a vapor pressure in the contact gas phase which is less than the maximum possible vapor pressure for that condition, but first, to have any evaporation, you must have some liquid. then the question becomes one of whether the vapor phase in contact is saturated or not with respect to water vapor.

One could dump liquid water at earth surface pressure into a blast furnace and the water will rapidly convert completely to steam (vapor), but the liquid water will not rise above the boiling temperature in the process, because it cannot be above boiling temp and remain liquid. That is, even if the system temp is far above boiling temp, the water will take time to get to that temp. The time can be extremely short, is all.

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• 6 months ago

When the vapor pressure of the water equals or exceeds the atmospheric pressure.

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• 6 months ago

sufficient heat

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