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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Hrushikesh on May 14, 2019, 10:08:49 PM

Title: ∆G
Post by: Hrushikesh on May 14, 2019, 10:08:49 PM
∆G=∆H-T∆S
     =(∆E+∆PV)-T(q/T)
     =q+w+P∆V+V∆P-q
     =-P∆V+P∆V+V∆P
     =V∆P
!!!!! This means that at constant P and T ∆G is always zero.
Please tell me is this correct or not.
If not tell me where.
Title: Re: ∆G
Post by: mjc123 on May 15, 2019, 04:36:05 AM
The equations ΔE = q + w and ΔS = q/T apply only to a system that undergoes no chemical changes. Then it is no surprise that at constant P and T ΔG = 0, because G is a state function. If there is a reaction, you have to consider the energy and entropy changes between reactants and products.