Gibb's free energy (very simple one)

  • Thread starter pari786
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Homework Statement



Calculate the equilibrium constant for the reaction forming nitric oxide at room temperature, 25C. G= 1.73x10^5 J/mol, H = 180.5KJ/mol an S = 24.8J/(mol.K)

Homework Equations



ln K = -G/RT

The Attempt at a Solution



I subsiuted ln K = (-1.73x10^5) / (8.3145x298.15)
ln K = -69.78
e^-69.78
I'm getting K as 4.95*10^-31

but the computer (where I submit online assignment ) is saying its wrong ... I've only one single attempt left ..can anyone see where I'm wrong.
Thanks and immediate help please!
 
Last edited:

Answers and Replies

  • #2
chemisttree
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Please show some more work. In particular, how did you obtain the value for G? What units did you use for R and S? Example: H is in KJ/mol and S is in J/molK. When I mess up these calculations, it is usually related to units.

BTW, for a very useful compilation of R in various units, consult the CRC Handbook of Chemistry and Physics. In the 84th edition (2003-2004), a very complete table is printed on page 1-54.
 

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