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Phase Changes

Phase Changes. What did one water molecule say to another water molecule about vapor? Don’t worry it’s just a phase he’ll cool down. Characteristics of Phase Changes. States of matter are also referred to as phases .

garth-church
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Phase Changes

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  1. Phase Changes What did one water molecule say to another water molecule about vapor? Don’t worry it’s just a phase he’ll cool down.

  2. Characteristics of Phase Changes • States of matter are also referred to as phases. • Phase Change: the reversible physical change that occurs when a substance changes from one state of matter to another

  3. PHASE CHANGES

  4. PHASE CHANGES

  5. Phase Change graphic Deposition Condensation Vaporization Sublimation Freezing Melting

  6. ENERGY AND CHANGES OF STATE • The energy of a substance is related to the motion of its particles. • If energy is ADDED to a substance its particles move faster. • If energy is REMOVED, its particles move slower.

  7. The temperature of a substance is a measure of the speed of its particles and therefore is a measure of its energy. • Steam has a higher temperature than liquid water, so particles in steam have more energy. • Solid to Liquid - the particles in the liquid have ______________________________________ • Steam to a liquid - the particles in the liquid have ______________________________________ • Liquid to a solid - the particles in the solid have ______________________________________ More energy than the particles in the solid Less energy than the particles in the gas Less energy than the particles in the liquid

  8. Endothermic vs. Exothermic • If energy is being added then the molecules are absorbing energy. This is called an ENDOTHERMIC PROCESS. • If energy is being taken away then the molecules are losing energy. This is an EXOTHERMIC PROCESS.

  9. Which are endothermic and which are exothemic? • Liquid to a solid - freezing • Gas to a liquid -condensation • Solid to a liquid - melting • Solid to a gas – sublimation • Liquid to a gas - vaporization

  10. Endothermic Exothermic

  11. Average Kinetic Energy = Temperature Temperature is a measurement of the average kinetic energy of the particles within a substance. Meaning that temperature measures movement of particles. Temperature is proportional to the average kinetic energy of the molecules of a substance. That means if you double the Kelvin temperature of a substance, you double the average kinetic energy of its molecules. When the average kinetic energy of the molecules goes up (a rise in temperature), the average speed of the molecules increases. A change in average kinetic energy is not directly proportional to a change in average speed.

  12. Using Temperature to Indicate Phase Change Whenever there is a plateau there is a phase change. This means that there is two phases of the substance at the same time. http://www.youtube.com/watch?v=WY6mcPaw8_k&feature=related

  13. Water Phase Change Graph E D 100 gas C Temperature º C. liquid B 0 A solid Heat (thermal energy)

  14. Water Phase Change Graph E D 100 gas C Temperature º C. liquid B 0 A solid Heat (thermal energy)

  15. Water Phase Change Graph E D condensing 100 boiling C Temperature º C. B freezing 0 melting A Heat (thermal energy) http://mutuslab.cs.uwindsor.ca/schurko/animations/waterphases/status_water.htm

  16. F Between B and C -Heat change in Potential Energy -Particles get farther apart -Temp. stays same -MELTING Between D and E -Heat change in Potential Energy -Particles get farther apart -Temp. stay same -Boiling Between A and B -Heat change in Kinetic Energy -Particles move Faster -Temp. increase -Solid Between C and D -Heat change in Kinetic Energy -Particles move Faster -Temp. increase -liquid Between E and F -Heat change in Kinetic Energy -Particles move Faster -Temp. increase -Gas D E C B A

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