Practice question · Match the pairs
Match each feature of a phase diagram to what it marks.
- Triple point
- Critical point
- Solid-liquid boundary
- Liquid-gas boundary
- The one condition where all three phases coexist
- Conditions at which melting and freezing balance
- Where liquid and gas cease to be distinguishable
- The vapour pressure curve of the liquid
Hints
- Two are single points and two are whole curves.
- The liquid-gas curve is exactly the vapour pressure plotted against temperature.
Show the answer
- Triple point → The one condition where all three phases coexist
- Critical point → Where liquid and gas cease to be distinguishable
- Solid-liquid boundary → Conditions at which melting and freezing balance
- Liquid-gas boundary → The vapour pressure curve of the liquid
Why
The triple point is a unique intersection, the critical point terminates the vaporisation curve, and the two boundaries are the loci of conditions where the neighbouring phases are in equilibrium.
Practise Physical Equilibria and Phase Diagrams
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