Ice sublimating to water vapor

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Discussion Overview

The discussion revolves around the phase change of ice sublimating directly to water vapor in a vacuum when the temperature is increased slightly above 0 degrees Celsius. It explores theoretical aspects of phase transitions, particularly under conditions of vacuum and varying temperatures.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • The original post questions whether ice can transition directly from solid to gas without becoming liquid when subjected to increased temperature in a vacuum.
  • One participant prompts others to consider the implications of the scenario by asking what they think would happen.
  • Another participant references the concept of the triple point, suggesting it may be relevant to the discussion.
  • A participant questions the necessity of increasing temperature for the ice to evaporate, seeking clarification on the conditions of the vacuum.
  • There is speculation that the original poster may be quoting from a textbook, implying a search for a definitive answer rather than engaging in exploration.
  • One participant emphasizes that vapor pressure is dependent on temperature and notes that vapor pressure of water exists at all temperatures above absolute zero, suggesting that this could affect the sublimation process.
  • Concerns are raised about the implications of maintaining a vacuum, particularly regarding the accumulation of vapor pressure and its effect on the fate of the ice.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of temperature increase for sublimation and the implications of vapor pressure in a vacuum. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

The discussion does not clarify assumptions about the nature of the vacuum or the specific temperature ranges involved, leaving these aspects open to interpretation.

Who May Find This Useful

This discussion may be of interest to those exploring thermodynamics, phase transitions, and the behavior of substances under varying pressure and temperature conditions.

bobkolker
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Suppose an ice cube is in a vessel and it is at a temperature slightly below 0 degrees Cesius. Suppose further that the inside of the vessel is a vacuum. If the temperature of the vessel is increased to slightly above zero Celsius and the vacuum is maintained would the state change in the ice cube be from solid to gas with no liquid in in between phase?

Bob Kolker
 
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What do you think would happen?
 
Are you saying that there is perfect vacuum maintained in the container? Why do you feel like you need to increase the temperature to get the ice to evaporate?
 
Chestermiller said:
Are you saying that
I suspect that the OP has been quoted from a textbook.He's just looking for the answer.
 
There is a saying (worth memorizing and repeating), "vapor pressure (in equilibrium) is dependent upon temperature alone."

Suffice it to also know that the vapor pressure of water is above zero at any temperature except for absolute zero itself (and absolute zero isn't achievable). In other words, the vapor pressure of water (whether it be solid ice or liquid water) is never actually zero.

Now if the vacuum is maintained, such that the vapor pressure never has a chance to accumulate, what is the ultimate fate of the ice at any given temperature?
 

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