phasechanges.pptx
- 2. Review: 3 Phases of Matter •Solid •Liquid •Gas
- 3. What is a Phase Change? •Is a change from one state of matter (solid, liquid, gas) to another. •Phase changes are physical changes because: • It only affects physical appearance, not chemical make-up. • Reversible
- 4. Water • Water exists on our planet in three states. • Ice, water, and water vapor • Water is different from other substances because it is less dense as a solid than liquid • What causes water to be in one phase or another?
- 6. Kinetic Energy •When temperature changes, molecules speed up/slow down resulting in a change in the average kinetic energy of molecules.
- 7. What happens during a phase change? •During a phase change, heat energy is either absorbed or released. •Heat energy is released as molecules move closer together. •Heat energy is absorbed as molecules move farther apart.
- 8. Potential Energy •During phase changes, temperature does not change. Molecules move closer together or farther apart, resulting in a change in the potential energy of the molecules.
- 9. Types of Phase Changes
- 10. Melting •Phase change from a solid to a liquid •Molecules move farther apart, and absorb heat energy
- 11. Freezing •Phase Change from a liquid to a solid •Molecule move closer together and release heat energy.
- 12. Vaporization (Boiling) •Phase change from a solid or liquid to gas. It occurs at the boiling point of matter or sublimation process. • Water 100° C • Table salt 1413° C • Diamond 4200° C Vaporization occurring at the surface of a liquid is called evaporation.
- 13. Evaporation •Type of vaporization in which a liquid turns to a gas on the surface of a liquid (occurs at all temperatures). •Molecules move farther apart, and absorb heat energy.
- 14. Evaporation- a Cooling Process As water in the perspiration evaporates from your skin it absorbs and carries away heat energy from your body.
- 15. Condensation •Phase change from a gas to a liquid. •Molecule move closer together and release heat energy.
- 16. Condensation Water vapor in surrounding air loses heat energy when it comes in contact with the cold glass. Water vapor condenses and becomes liquid drops of water.
- 17. Sublimation •Phase change from a solid to a gas. •Molecules move farther apart, and absorb heat energy.
- 18. Deposition •Phase change from a gas to a solid. •Molecules move closer together and release heat energy.
- 19. Graphing a Phase Change
- 20. Temperature Comparisons Boiling Point of H2O 212 F 100 C Melting Point of H2O 32 F 0 C Freezing Point of H2O 32 F 0 C
- 21. •Boiling Point - The temperature at which a liquid changes into a gas. •Melting Point - The temperature at which a solid changes into a liquid. •Freezing point - The temperature at which a liquid changes into a solid. •Freezing point and melting point of a substance are the same temperature.
- 22. Summary 334 Joules 2260 Joules
- 23. Add the correct terms to the diagram… Evaporation Melting Condensation Freezing Sublimation