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Participant

Join Date: Sep 2017
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Degree of Freedom During Phase Change

09/02/2017 12:20 PM

During phase change,

number of components=1

number of phases=2

so by Gibb's phase rule,

degree of freedom=1

But we need dryness fraction in addition to temperature (or pressure) to completely identify the state of the system, so how is degree of freedom =1 justified?

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Guru

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#1

Re: Degree of freedom during phase change

09/02/2017 12:29 PM
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Guru

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#2

Re: Degree of freedom during phase change

09/02/2017 1:21 PM

Depends on the system

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Guru

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#3

Re: Degree of Freedom During Phase Change

09/02/2017 9:54 PM

Yes you can have variables...but that doesn't effect the degrees of freedom...

http://www.colby.edu/chemistry/PChem/notes/GibbsPhaseRule.pdf

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#4

Re: Degree of Freedom During Phase Change

09/03/2017 11:34 PM

When you enter "dryness" into the system, your component count is now 2.

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Guru

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#5

Re: Degree of Freedom During Phase Change

09/05/2017 1:53 PM

You have to learn to count all over again. Moisture and compound X is not a single component system.

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