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Topic: Finding the free energy  (Read 2236 times)

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Offline opti384

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Finding the free energy
« on: September 11, 2010, 07:04:13 AM »
I have the reaction 2Cr(s) + 3Cu^2+ (aq) → 2Cr^3+ (aq) + 3Cu(s) E^° = 0.43 V. and I have to find the
∆G^°  in KJ mol ^-1. So I came across the equation ∆G^° = -nFE^°. The answer is -6 × 96500 × 0.43  / 1000. At first I though it was -6 × 96500 × 0.43. I think the /1000 comes because I have to find ∆G^°  in KJ mol ^-1. Is ∆G^° originally expressed in J mol ^-1?

Offline MrTeo

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Re: Finding the free energy
« Reply #1 on: September 11, 2010, 07:40:43 AM »
Yes, because

$$ 1\;V=\frac{1\;J}{1\;C} /$$

F is measured in Coulombs (it's the charge of a mole of electrons) and n is adimensional.
The way of the superior man may be compared to what takes place in traveling, when to go to a distance we must first traverse the space that is near, and in ascending a height, when we must begin from the lower ground. (Confucius)

Offline opti384

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Re: Finding the free energy
« Reply #2 on: September 11, 2010, 09:22:58 AM »
I see.

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