Using the Clapeyron equation, only the slope of the equilibrium is determined, not the actual position of the reaction in pressure-temperature space.
• Relates saturation properties
• Start with MR #3:
• During phase change, T=constant
• In general, during phase change . That is, v changes but P does not!
• MR #3 thus becomes (after evaluating across phase change)
• Since Tds = dh − vdP and dP=0,
• In general, we can replace ‘f’ and ‘g’ with any phase change (e.g. solid to liquid):