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I am trying to find a vapor pressure of sublimating ice as a function of thermal energy being absorbed by ice. Basically, I am starting with a sample of ice (t=200K) in a vacuum. From there, I am heating the ice slowly using a heating plate, causing a non-zero vapor pressure of gaseous water to form. Assuming the vacuum will be held (i.e. vapor pressure of water impacts the vacuum negligibly), is it possible to create a relation between the vapor pressure and the thermal power being absorbed by the ice?

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  • $\begingroup$ Is it in a closed container? If so, the thermodynamic properties of water vapor and ice are known, including densities and internal energies and equilibrium vapor pressures as functions of temperature. So, for any temperature, you can determine the internal energy of the combination and, from that, the amount of heat added. $\endgroup$ – Chet Miller Sep 23 '18 at 13:16
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The vapour pressure of ice at 200K is very low, as sublimation occurs the ice gets colder due the phase change. Assuming your vacuum is maintained the ice would continue to get cooler. The vapour pressure of the ice is a function of its temperature, the power being absorbed would effect the temperature, you would need to know the size of the ice cube etc.

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  • $\begingroup$ But there is a heating plate under the ice adding thermal energy, so wouldn't the ice get warmer despite the phase change? $\endgroup$ – Peter Connors Sep 23 '18 at 18:28
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    $\begingroup$ Yes it would as long as you add enough power, but you need to know the size of the cube and power output of the plate to know how fast the temperature will rise. $\endgroup$ – PhysicsDave Sep 23 '18 at 19:58
  • $\begingroup$ Thank you, and is there a resource you know of that would help me learn how to relate those things in some sort of derivation? $\endgroup$ – Peter Connors Sep 24 '18 at 23:57
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    $\begingroup$ Peter here is an interesting link: lyotechnology.com/vapor-pressure-of-ice.cfm. What your are asking is from the discipline called physical sciences or physical chemistry which I took in 2nd year engineering. Not a simple subject. Looks like you really don't need to heat it just make a sample cold and use a vaccuum, there should be enough heat from the surroundings to get a decent graph. $\endgroup$ – PhysicsDave Sep 25 '18 at 0:06

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