How Does ΔH Change with Temperature for Water to Vapor Conversion?

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SUMMARY

The discussion centers on the enthalpy change (ΔH) during the conversion of water to vapor, specifically noting that the process releases -241 KJ/mol for water vapor and -284 KJ/mol for liquid water. The energy required to convert liquid water at 25°C to vapor is 44 KJ/mol. It is established that ΔH varies with temperature, prompting the inquiry about a formula to calculate this variation.

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  • Understanding of Hess' Law
  • Basic thermodynamics concepts
  • Knowledge of enthalpy changes in phase transitions
  • Familiarity with the concept of standard state conditions
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  • Research the Clausius-Clapeyron equation for phase changes
  • Learn about the heat of vaporization and its temperature dependence
  • Study the concept of standard enthalpy of formation
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Conductivity
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So when they said that to produce water vapor at standard state it releases -241 KJ/mol
and liquid water -284 KJ/mol

You can't create water vapor at standard temperature but I assume they used Hess' law
Anyway, my question is when you change from water to vapor you need 44KJ/mol

So that would be the energy required to change from 25 C liquid to 25 C vapor.
Does it change for example when you want to change it from another temperature?
 
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Yes. Do you know a formula for the variation of ΔH with temperature?
 

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