Phase Transitions The above picture shows a block of solid Ar melting and subliming after exposur to aire at roughly room temperature. http://en.wikipedia.org/wiki/Phase_transition

Phase Diagram of H2O http://people.virginia.edu/~lz2n/mse209/Chapter9-p1.pdf See also: http://www1.lsbu.ac.uk/water/phase.html

Examples Chapter 12 4.) A system consists of 1024 molecules of water. The initial state is pure vapor at 373 K and atmospheric pressure. The water is heater at constant pressure to T=700K, subsequently compressed isothermally to a pressure of 230 atm, cooled to 373 K a this constant pressure, and finally allowed to expand isothermally to atmospheric pressure. The final state is pure liquid. What is the net change in the system’s internal energy? What is the net change in the system’s chemical potential? 5). The top of Mt. Everest is 8,854 meters above sea level. Calculate the temperature at which water boils at the summit. 7). The vapor-pressure curves at the triple point display a cusp (if you look carefully enough, and if the person drawing the diagram was careful enough). Explain why this must be the case. a). Specifically, near the triple point for water vg/vl=2.06x105 vs/vl=1.09 and the latent heats are 0.47, 0.53 and 0.062 eV/molecule (for vaporization, sublimation and melting respectively).

From J.R. Waldram “The Theory of Thermodynamics”

Alloy phase diagram of Cu-Ni http://people.virginia.edu/~lz2n/mse209/Chapter9-p1.pdf

Eutectic Phase Diagram NOTE: at a given overall composition (say: X), both the relative amounts of the two phases (a,b or c,d) AND the composition of one (or possibly both) depend on the temperature http://www.tulane.edu/~sanelson/geol212/2compphasdiag.html