Volume change when liquid goes to solid.

[ladil]

Hello!

I need some help regarding a simple matter...

How do I derive an equation for the increase in volume when a liquid goes to a solid state when I know the density of the liquid?

 

[K^2]

Most liquids reduce volume when they become solid. Water is one of the very few exceptions. Between the enthalpy of fusion and pressure-temperature diagram, you might be able to get an estimate, but generally, density change at phase transition is something you need to look up for specific material.

 

[ladil]

ok. Thanks for the help. Ill check it out.
Lets say it is water that becomes ice. Is there any easy way to derive an equation for predicting the increase in volume?

 

[K^2]

The slope of the PT diagram should tell you how much the entropy changes at transition, and knowing transition temperature and specific heat of fusion, you should be able to figure out how much energy goes into volume changed at given pressure, which should give you the density change. But I'm having a bit of trouble deriving this. Sorry, thermodynamics has never been my strong field.