Chemical Forums
Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Ali-x on April 17, 2015, 07:30:05 AM
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Hello everybody,Lately i mixed up with a plot in thermodynamics
Differentiation of Gibbs energy over differentiation of temperature at constant pressure is -S
It shows that when T is increasing S is not increasing,it is constant(better to say it is linear)
So this interpretation doesn't sound good because when you heat something you increase its entropy.
Could any body help me?
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To say that dG/dT = -S does not necessarily imply that S is constant.
However, if it is not, why is there no dS/dT term?
Write the expression for G, differentiate it, and see if you can eliminate everything except -S.
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Many thanks for your reply
You i got confused because the G derivative expression says -s but my knowledge about increasing temperature doesn't imply with pure theoretical derivation.
Is it kind of shortcoming of theory and empirical?
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To say that dG/dT = -S does not necessarily imply that S is constant.
However, if it is not, why is there no dS/dT term?
Write the expression for G, differentiate it, and see if you can eliminate everything except -S.
Many thanks for your reply
You i got confused because the G derivative expression says -s but my knowledge about increasing temperature doesn't imply with pure theoretical derivation.
Is it kind of shortcoming of theory and empirical?
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No. G = H - TS
Differentiate that (assuming H and S are not constant with temperature).
What does (dH/dT)P equal? What does (dS/dT)P equal? So...