Chemical Forums
Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: davidmet on September 15, 2013, 05:27:42 PM
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Hi, i just want you to clarify me something about free gibbs energy in equilibrium; according to me, free gibbs energy in equilibrium is equal to 0 because in a reversible reaction the products and the reagents should have the same energy, so that the reaction would be reversible,( if they don´t have the same energy, for example if the energy of reagents is bigger than the energy of the products, then the reaction won´t be reversible, because the products would not have the required energy for their conversion to reagents) i just want you to tell me if this is correct or not and why,thanks
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It's wrong. Any reaction that can reach an equilibrium is considered to be "reversible" by definition - because reactants are being converted to products at the same rate products are being converted to reactants when equilibrium is reached. Only when the ΔG is so large that the equilibrium constant approaches infinity (forward rate >> backward rate) is a reaction considered "irreversible". An example might be dissociation of a concentrated acid like HCl in water.
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So for example, suppose we have the reagents of a reversible reaction; before it reaches equilibrium the free gibbs energy will be less than 0 because the reaction moves from left to right and the products are being formed, and when it reaches equilibrium free gibbs energy will be 0? am i right?
And if that is correct then in equilibrium who has more energy: reagents or products? or the energy of both is the same?