The change in temperature of moist air

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Discussion Overview

The discussion revolves around the change in temperature of moist air when a certain mass of water vapor condenses. Participants explore the implications of this phase change on temperature, considering both theoretical and practical aspects of thermodynamics.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • One participant states that the moist air will warm due to condensation and provides the heat of vaporization and specific heat values for calculations.
  • Another participant questions the magnitude of the temperature change, asking for clarification on how much too large the initial value seems.
  • A different participant introduces the concept of equilibrium and suggests considering the p-v diagram and "quality" when some of the air condenses while some does not.
  • One participant reminds another to include the mass of the air in their calculations, implying that this is crucial for an accurate assessment of temperature change.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are multiple approaches and considerations regarding the calculations and the underlying thermodynamic principles.

Contextual Notes

There are unresolved assumptions regarding the conditions of the moist air and the specifics of the calculations, such as the impact of the mass of the air and the state of equilibrium.

Who May Find This Useful

Students and individuals interested in thermodynamics, particularly those studying phase changes and heat transfer in moist air systems.

ssonia
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Homework Statement



1 kg of moist air and 1 g condenses.

What will the change in the temperature of the moist air be?

Heat of Vaporization = 2.5*10^6 J/kg

2. The attempt at a solution

The moist air will warm due to condensation.

Heat of Vaporization=2.5*10^3 J/g

Specific heat at constant pressure = 1004 J/K.kg = 1.004 J/K.g

My next step was to divide the heat of vaporization with the specific heat to get the temperature in Kelvin, however the value seems to large.

Any help would be grateful...Thanks.
 
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How much too large?
 
ssonia said:

Homework Statement


1 kg of moist air and 1 g condenses.

What will the change in the temperature of the moist air be?
Assuming equlibrium, if some of it condenses and some of it does not, where on the p-v diagram must you be? Hint: think "quality".
 
Did you remember to include the mass of the air (1kg) in the calculation?
 

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