1. Energy Change:
* Melting (solid to liquid): Energy is absorbed by the substance to break the bonds holding the molecules in a fixed, rigid structure.
* Freezing (liquid to solid): Energy is released as the molecules slow down and form a more ordered structure.
* Vaporization (liquid to gas): Energy is absorbed to overcome the intermolecular forces holding the liquid together.
* Condensation (gas to liquid): Energy is released as the gas molecules slow down and come closer together.
* Sublimation (solid to gas): Energy is absorbed to directly convert a solid into a gas, bypassing the liquid phase.
* Deposition (gas to solid): Energy is released as the gas molecules directly convert into a solid.
2. Molecular Arrangement:
* Solid: Molecules are closely packed and arranged in a fixed, rigid structure.
* Liquid: Molecules are closer together than in a gas but have more freedom to move around.
* Gas: Molecules are far apart and move randomly at high speeds.
3. Density Change:
* Solids are typically denser than liquids.
* Liquids are typically denser than gases.
4. Entropy Change:
* Entropy (the degree of disorder) increases as a substance transitions from solid to liquid to gas.
5. Physical Properties:
* Melting point: The temperature at which a solid transitions to a liquid.
* Boiling point: The temperature at which a liquid transitions to a gas.
* Freezing point: The temperature at which a liquid transitions to a solid.
* Sublimation point: The temperature at which a solid directly transitions to a gas.
* Deposition point: The temperature at which a gas directly transitions to a solid.
Note: The specific energy changes, molecular arrangement, and physical properties will vary depending on the substance and the conditions involved.
