Energy and Molecular Order Changes: Phase Changes

The changes of different phases of matter to another phase

1. Energy and molecular order changes PHASE CHANGES

2. S O L I D G A S L I Q U I D Heat Energy Absorption / Kinetic Energy Increase Sublimation Fusion Vaporization (Melting) (Boiling) Solidification Condensation (Freezing) (Liquefying) Deposition Heat Energy Release / Kinetic Energy Decrease DIAGRAM OF ENERGY CHANGES

3. MELTING POINT - the temperature at which the solid melts to form the liquid FREEZING POINT - the temperature at which the liquid freezes to form the solid

4. EVAPORATION / VAPORIZATION – liquid particles that overcome the attractive forces of the neighbouring particles and escape the process, hence, becoming a gas BOILING POINT – when a liquid is heated in an open container, its vapour pressure will rise until it equals the pressure of the atmosphere above the liquid causing it to boil.

5. CONDENSATION – the reverse process, happens when particles in the vapour pressure are cooled and returns to liquid SUBLIMATION – the solid phase passes directly into the gas phase

6. DEPOSITION – the change from the gas to the solid phase without passing the liquid phase; the reverse of sublimation

7. Reverse phase changes occur at the same temperature and if they occur at same rate, the phases are said to coexist in dynamic equilibrium. Earning the title, “Triple Point”

8. SOLID LIQUID MELTING SOLID GAS SUBLIMATION LIQUID SOLID FREEZING LIQUID GAS VAPORIZATION GAS SOLID DEPOSITION GAS LIQUID CONDENSATION