Calculating Free Energy: Standard Enthalpy and Entropy at 32C

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Discussion Overview

The discussion revolves around calculating the Gibbs free energy for a chemical reaction, given the standard enthalpy and entropy values at a specific temperature (32°C). The focus is on the application of the Gibbs free energy equation and the correct handling of units in the calculation.

Discussion Character

  • Technical explanation, Mathematical reasoning, Debate/contested

Main Points Raised

  • One participant presents a calculation for Gibbs free energy using standard enthalpy and entropy values, resulting in a specific numerical answer.
  • Another participant references the Gibbs free energy equation (G = H - TS) to clarify the calculation method.
  • There is a question raised about whether the initial calculation was correct.
  • Some participants point out a potential issue with unit conversion, specifically the addition of kiloJoules and Joules, but later clarify that the conversion was correctly handled by converting entropy from J to kJ.
  • A later reply acknowledges a misunderstanding regarding the unit conversion in the initial calculation.

Areas of Agreement / Disagreement

Participants express disagreement regarding the correctness of the initial calculation, particularly about unit handling. However, there is a recognition that the conversion of units was ultimately done correctly.

Contextual Notes

There are unresolved aspects regarding the clarity of unit conversions and the implications of using different units in the calculation of Gibbs free energy.

Soaring Crane
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Calculate the gibbs free energy for a reaction which has a standard enthalpy = -196kJ/mol and standard entropy = 151 J/K mol at 32C.

G = -196 KJ/MOL -[-305.15 K*0.15] = -242KJ

Thank you.
 
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Isn't that what I did?
 
You're adding kiloJoules to Joules...
 
dav2008 said:
You're adding kiloJoules to Joules...

No, I think he did not. Because he converted 151 J to 0.15 kJ:

Soaring Crane said:
G = -196 KJ/MOL -[-305.15 K*0.15] = -242KJ
 
PPonte said:
No, I think he did not. Because he converted 151 J to 0.15 kJ:
Oops didn't notice that.
 

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