Wednesday, January 19, 2011

Question about Degrees of Freedom

Hello Everyone,

For those who are new here, this blog is about AMIE study materials, info & notes.Currently I am going through Material Science. So all I post here are related to Material Science for next few days.

I have been going through old question papers, wherein there is a peculiar question which can be stated as "Calculate degree's of freedom in water and ice under 1 atm pressure?".


I have some difficulty in answering this question. Please help me by telling me which among the following is right?


Answer 1)
Gibbs phase rule says F = C - P + 2. Here C = 1, P = 2 at 1 atm pressure hence F = 1


Answer 2)
Gibbs phase rule says F = C - P + 2 but since pressure is constant the formula becomes F = C - P + 1 hence F = 0 with C = 1 & P = 2. 



I am not sure of the answer. Please do help me to decide on the same by suggesting your answer and proof if any.


with warm regards
allmyposts

1 comment:

  1. I have seen your both answers.
    Answer 2) is correct.

    because : Gibbs given rule of DOF is based on following :
    F = C - P + V
    where V is No. variables (Environmental like presure, Temprature, Volume. Please related it with it with PV/T = R )
    You have already declaced that atmospharic pressue is 1 which is constant ( not varing with time) so, gibbs formulla will be modified with V=1.

    Further, I also want to contribute in you blog.
    I am also prepareing for Section A papers.
    I will go for II time in June-2011,
    my email is manojnegi90@gmail.com

    ReplyDelete

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