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changes in entrophy and delta H

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Rate your uni — help us build a league table based on real student views 19-08-2015
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    I know entrophy increases so that excludes A and B but how do I know the sign of delta H, is there any reasoning given only this information?
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    They want you to work it out, delta G = delta H - T delta S, the reaction must be feasible. So I think the answer is C, because it is feasible at any temperature when delta H is positive, D will only happen if the temperature is high enough
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    Surely you are breaking bonds in the liquid phase, to form free gas molecules. Breaking bonds requires energy, so delta H is positive???
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    Yes, Delta H much be positive as you are breaking the intermolecular forces.
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    but the bonds broken = the bonds formed so the delta H is the same, no?
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    No ... you are breaking the intermolecular forces between the liquid molecules and need to put energy in to evaporate it into the gas. (ie this is an endothermic process)
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    yeh i just came back to say how silly of me! I thought it over, looked into that too much at the start...now that is one mistake I can not be doing in a few weeks!
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    (Original post by sokas)
    They want you to work it out, delta G = delta H - T delta S, the reaction must be feasible. So I think the answer is C, because it is feasible at any temperature when delta H is positive, D will only happen if the temperature is high enough
    I did the same thing to start lol

    I would like to say a massive thank you to all of you: Krismas, Hoofbeat & sokas.
Updated: May 19, 2005
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