Latent heat vaporization vs fusion

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Discussion Overview

The discussion revolves around the comparison of latent heat of vaporization and latent heat of fusion (melting), exploring why the former is greater than the latter. Participants examine the implications of intermolecular distances and density changes during phase transitions.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions why the latent heat of vaporization is greater than that of fusion, suggesting that atoms in a liquid state are already far apart, implying less energy is needed to transition to gas.
  • Another participant counters that atoms in a liquid are not significantly far apart, noting that the small change in density during melting indicates minimal change in intermolecular distance.
  • A third participant agrees with the previous point but adds that the behavior observed is specific to water due to its anomalous properties, highlighting the significant density change from liquid to gas compared to solid to liquid.
  • One participant states that the density of a phase serves as a good indication of intermolecular distance.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between intermolecular distances and the latent heats of vaporization and fusion, indicating that multiple competing perspectives remain without consensus.

Contextual Notes

The discussion includes assumptions about intermolecular distances and density changes that may not be universally applicable across all substances, particularly regarding water's unique properties.

SandeshPhy
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Why is the latent heat of vaporisation greater than that of fusion(melting)?
I mean in liquid state,atoms are already far apart, so it must require less energy to make them gas(far apart) as forces(electric in nature) between molecules decrease with distance.
 
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I don't think that atoms in liquid are far apart. Actually, when solid melts there is small change in density, implying that there isn't quite much change in intermolecular distance. e.g water is virtually densor than ice
 
ZealScience said:
I don't think that atoms in liquid are far apart. Actually, when solid melts there is small change in density, implying that there isn't quite much change in intermolecular distance. e.g water is virtually densor than ice

That is only the case for water due to anomalous behavior.
Yes there a change in density from liquid to gas change while there is little from solid to liquid.
 
And density of a phase is a god indication of intermolecular distance.
 

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