- #1
DLawless
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I notice that water phase diagrams provided online always seem to show a rather linear behaviour for the solid-liquid boundary (and an extremely steep slope).
How is this modeled mathematically? Say we use the Clapeyron equation with ΔH and ΔV_m being constant, as online example problems (meant for students) do. Integration with this yields a ln(T2/T1) for example--not the equation of a straight line. So where does the almost straight line, which suggests that P=kT for some very large negative k, come from? And how valid is it really to model ΔH and ΔV_m as constant, if this doesn't produce a line that looks much like the diagrams show?
How is this modeled mathematically? Say we use the Clapeyron equation with ΔH and ΔV_m being constant, as online example problems (meant for students) do. Integration with this yields a ln(T2/T1) for example--not the equation of a straight line. So where does the almost straight line, which suggests that P=kT for some very large negative k, come from? And how valid is it really to model ΔH and ΔV_m as constant, if this doesn't produce a line that looks much like the diagrams show?