Boiling point

[Agustina Santa Cruz 2F]

Is boiling point always found at equilibrium (deltaG=0)? If so, why?

[Alex Mele 2A]

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.

[Sahiti Annadata 3D]

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.

[Isabelle Hales 1J]

Hi! Going off of this, is the melting point also found at equilibrium (deltaG = 0)?

[Nick Pascua 2L]

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.

[Astha Patel 2J]

Phase changes occur at equilibrium because all the energy is used for changing the states rather than heating up the compounds.

[Taylor K 2D]

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!!

[Neha Jonnalagadda 2D]

Phase changes occur at equilibrium?

[Fiona H 2E]

I believe that liquid and gas phases are in equilibrium at the boiling temperature

[805401611]

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!