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Topic: Concentration of product from Gibbs energy  (Read 795 times)

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Offline pjuty

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Concentration of product from Gibbs energy
« on: March 29, 2020, 02:55:35 PM »
Hi there,
I have problem with this because I don't know how to calculate it.
Example:
Calculate the concentration of the product (RCOOR ester) in the reaction mixture when
esterification is carried out at 60 ° C under reflux (nothing is leaving the reactor). The reaction mixture is stirred and heated until the system is complete in equilibrium.

R-COOH + R-OH = R-COOR + H 2 O

The gas constant is 8.314 J · K -1 · mol -1.
Change of free enthalpy of reaction (Gibbs energy) ΔG r = -2 kJ.mol -1.
The starting concentrations of c0 acid and alcohol are the same and c0 = 1 mol.dm

I tried to calculate it but I get double the product concentration which is nonsensical

Thank you very much for your help

Offline chenbeier

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Re: Concentration of product from Gibbs energy
« Reply #1 on: March 29, 2020, 03:03:04 PM »
What is the formula for dG in consideration of an equilibrium reaction?

Offline pjuty

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Re: Concentration of product from Gibbs energy
« Reply #2 on: March 29, 2020, 03:11:03 PM »
I attached the file as I tried to solve it

Offline pjuty

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Re: Concentration of product from Gibbs energy
« Reply #3 on: March 29, 2020, 03:39:39 PM »
I managed to solve the task

Thank you

Offline chenbeier

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Re: Concentration of product from Gibbs energy
« Reply #4 on: March 29, 2020, 03:52:03 PM »
To solve Gibbs equation is ok, but to solve the equilibrium i would think again.
The start amont is  1 mol of alcohol  and acid at start.
But in equilibrium you have all compounds present.
So develop k again for equilibrium.

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