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Topic: Thermodynamic assumptions  (Read 5106 times)

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Offline Knockabout

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Thermodynamic assumptions
« on: August 21, 2007, 06:02:08 AM »
Hi, I'm in the middle of determining ∆G° using the Van't Hoff equation on data from a differential scanning calorimeter. DNA denaturation was measured.

The values are calculated following our course manual, however, I'd like to better understand some of the assumptions taken during these calculations.

1) ∆H° and ∆S° are independent of temperature (or at least in the interval of interest here, I guess).
-This assumption must be based on ∆Cp = 0.. Is that an okay assumption?

2) ∆H = ∆H° (the measured enthalpy - from the DSC - equals the standard enthalpy).
-I asked my supervisor about this one, and got the answer that, "because my solutions is very diluted it's okay".. What's the reasoning behind this?

I hope somebody can help, any ideas are much appreciated  ;D

Thanks,
Michael
« Last Edit: August 21, 2007, 06:49:42 AM by Borek »

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