Boiling point
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Re: Boiling point
Boiling points do occur at delta G = 0 because there is no change in temperature. Energy is going toward the phase transition and not toward heating up the substance.
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Re: Boiling point
At boiling point, the change in temperature is zero so the change in enthalpy is also zero. Since the change in enthalpy is zero, the entropy change is zero, offset by the energy required for vaporization.
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Re: Boiling point
Hi! Going off of this, is the melting point also found at equilibrium (deltaG = 0)?
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Re: Boiling point
Isabelle Hales 1J wrote:Hi! Going off of this, is the melting point also found at equilibrium (deltaG = 0)?
Yes, I believe so. As stated above, although both processes are dealing with different state changes, the change in temperature is zero and thus the entropy, Gibbs free energy, and change in enthalpy is zero.
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Re: Boiling point
Phase changes occur at equilibrium because all the energy is used for changing the states rather than heating up the compounds.
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Re: Boiling point
Isabelle Hales 1J wrote:Hi! Going off of this, is the melting point also found at equilibrium (deltaG = 0)?
I would think so! I'm pretty sure that at the temp for all phase changes (melting point, boiling point, etc) that G=0!!
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Re: Boiling point
I believe that liquid and gas phases are in equilibrium at the boiling temperature
Re: Boiling point
Yes, the boiling point is always found at equilibrium with delta G = 0. This is because this is the point where liquid and vapor are in equilibrium as well. If delta G > 0, then water does not evaporate spontaneously and will irreversibly condense to liquid water. If delta G < 0, then water evaporates spontaneously and irreversibly. Hope that helps!
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