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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Soulja on December 25, 2021, 03:42:21 PM

Title: Does ∆G° Change with temperature?
Post by: Soulja on December 25, 2021, 03:42:21 PM

I was always under the assumption that the "naught" symbol, whether it be delta H naught or delta S naught meant that the value was tabulated under standard conditions (i.e. 1 ATM, 293 K, etc). However, after doing a problem that asked for the Keq at a non-standard temperature and getting it wrong, I was told that I needed to calculate a new value of ∆G° using the new temperature. Doesn't that defeat the entire purpose of using the "naught" symbol? Does ∆G° change with temperature?

Thanks!!!!

Title: Re: Does ∆G° Change with temperature?
Post by: Corribus on December 26, 2021, 05:35:31 PM

Temperature is not part of the definition of the standard state. So yes, ΔG° changes with temperature, by G = H - TS. H and S are also strictly not temperature independent either, although over small temperature changes it's not a bad approximation.