Question

Compare the deltaS fusion with the deltaS vaporization for water. Are they reasonable in terms of the relative disorder of the states of matter?

deltaH fusion= 6.10 kJ/mol and deltaH vap= 40.7 kJ/mol

Answer 1

Yes.

deltaH fusion = heat required to change a substance from a solid (ice) to a liquid (water)

deltaH vap = heat required to change a substance from a liquid (water) to a gas (steam)

In solids, the molecules are very close together and the molecules have little freedom to move, as you would see in the case of ice. So , disorderness is vey less.

In the case of a liquid, the molecules are closely spaced, though not as closely spaced as a solid, they have more freedom to move and the intermolecular forces are weaker that that of a solid. Thus a liquid can flow, unlike a solid. So, disorderness of liquid is greater than solid.

Now in a gas, the molecules are sufficiently far apart that there are little to no attractive forces. Because of this a gas can easily be compressed and take the shape of the container. So disorderness of gas is greather than both liquid and solid.

Now as you heat a solid turning it into a liquid, you increase the kinetic energy of its molecules, moving them further apart until the forces of attraction are reduced to allow it to flow freely.

Now as you heat a liquid, turning it into a gas, the kinetic energy of the molecules are increased to a point where there are no forces of attraction between the molecules.

The energy required to completely separate the molecules, moving from liquid to gas, is much greater that if you were just to reduce their separation, solid to liquid.

Hence , the reason why the latent heat of vaporization is greater that the latent heat of fusion.

Therefore,

the given values are reasonable in terms of the relative disorder of the states of matter.