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Unformatted text preview: , and holds: G m = G m and S m = S m-S m = r T where r is the transition heat of phase to phase and T is the transition temperature. The following holds: r = r and r = r -r . urther S m = G m T p so G has a twist in the transition point. In a two phase system Clapeyrons equation is valid: dp dT = S m-S m V m-V m = r ( V m-V m ) T or an ideal gas one Fnds for the vapor line at some distance from the critical point: p = p e-r /RT There exist also phase transitions with r = 0 . or those there will occur only a discontinuity in the second derivates of G m . These second-order transitions appear at organization phenomena . A phase-change of the 3rd order, so with e.g. [ 3 G m / T 3 ] p non continuous arises e.g. when ferromagnetic iron changes to the paramagnetic state....
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- Spring '10