1. Phases of Matter and Phase Changes

2. Phase Depends on strength of forces of attraction between particles. Depends on strength of forces of attraction between particles..

3. Solids Definite shape and volume. Definite shape and volume. Most dense phase (exception is water!). Most dense phase (exception is water!). Difficult to compress. Difficult to compress. Particles vibrate in fixed positions Particles vibrate in fixed positions Regular crystalline lattice structure. Regular crystalline lattice structure. Highest attraction between particles. Highest attraction between particles. Note: Amorphous solids include Note: Amorphous solids include glass, plastic, wax, and silly putty glass, plastic, wax, and silly putty

4. Liquids Definite volume Definite volume No definite shape No definite shape Hard to compress Hard to compress Particles slide past each other Particles slide past each other Forces of attraction between particles still high Forces of attraction between particles still high

5. Gases No definite shape or volume No definite shape or volume Expands to fill container Expands to fill container Lowest density Lowest density Density depends on pressure Density depends on pressure Little attraction between particles Little attraction between particles “Vapor” = a gaseous state of something that is normally liquid “Vapor” = a gaseous state of something that is normally liquid (Ex: water vapor) (Ex: water vapor)

6. Phases Applet Short Summary video on phases: Short Summary video on phases: http://www.youtube.com/watch?v=s- KvoVzukHo&safe=active http://www.youtube.com/watch?v=s- KvoVzukHo&safe=active http://www.youtube.com/watch?v=s- KvoVzukHo&safe=active http://www.youtube.com/watch?v=s- KvoVzukHo&safe=active http://www.harcourtschool.com/activity/stat es_of_matter/ http://www.harcourtschool.com/activity/stat es_of_matter/ http://www.harcourtschool.com/activity/stat es_of_matter/ http://www.harcourtschool.com/activity/stat es_of_matter/

7. Changes in Phase Gas CondensationVaporization (Boiling or Evaporating) Liquid SolidificationMelting (fusion) Solid

8. Let’s Skip a Phase Sublimation Sublimation Directly from the solid phase to the gas phase. Directly from the solid phase to the gas phase. Happens with substances with weak intermolecular forces of attraction Happens with substances with weak intermolecular forces of attraction They separate easily! They separate easily! Ex: CO 2 (s) dry ice, Iodine Ex: CO 2 (s) dry ice, Iodine CO 2 (s) → CO 2 (g) http://www.youtube.com/watch?v=8tHOVVgGkp k

9. Energy Energy = capacity to do work or produce heat. It can be anything that causes matter to move or change direction. Energy = capacity to do work or produce heat. It can be anything that causes matter to move or change direction. Ex: electrical, atomic, mechanical, chemical Ex: electrical, atomic, mechanical, chemical Energy and the 4 states of matter: Energy and the 4 states of matter: http://www.youtube.com/watch?v=88tK5c0wgH4&safe=active http://www.youtube.com/watch?v=88tK5c0wgH4&safe=active http://www.youtube.com/watch?v=88tK5c0wgH4&safe=active

10. Law of Conservation of Energy Energy can’t be created or destroyed, just transferred from one form to another Energy can’t be created or destroyed, just transferred from one form to another

11. PE vs. KE Potential Energy stored energy Potential Energy stored energy Energy can be stored in bonds between atoms and released during chemical rxns. Kinetic Energy energy of motion Kinetic Energy energy of motion All atoms are moving and vibrating unless at absolute zero

12. Heat Energy A form of energy that increases the random motion of particles A form of energy that increases the random motion of particles Measured in Joules or calories. Measured in Joules or calories. http://www.youtube.com/watch?v=f1eAOygDP5s&safe=active

13. Heat Flow Heat energy travels from an object of higher temp. to one of lower temp. until both reach the same temp. Heat energy travels from an object of higher temp. to one of lower temp. until both reach the same temp.

14. Temperature Measure of the average kinetic energy (motion) of all the particles in a sample. Measure of the average kinetic energy (motion) of all the particles in a sample. Not a form of energy!!! Not a form of energy!!! But if you add heat energy or take it away, it causes particles to move faster or slower and thus changes the temp. But if you add heat energy or take it away, it causes particles to move faster or slower and thus changes the temp.

15. Temperature Scales Used in Chemistry Celsius Fixed points of scale based on the freezing point and boiling point of water Fixed points of scale based on the freezing point and boiling point of water 0 °C = water freezes, 100 °C = water boils 0 °C = water freezes, 100 °C = water boilsKelvin Scale based on lowest temperature possible Scale based on lowest temperature possible 0 K = absolute zero 0 K = absolute zero

16. Temperature Scales and Conversions K = ˚C + 273

17. Absolute Zero Temperature at which particles have slowed down so much they no longer possess any kinetic energy. Temperature at which particles have slowed down so much they no longer possess any kinetic energy. 0 Kelvin -273° Celsius

18. Heat vs. Temperature Teacup vs. Bathtub Teacup vs. Bathtub Both at 25˚C Both at 25˚C Which one contains more heat energy? Which one contains more heat energy? Which one has the greater average KE? Which one has the greater average KE?

19. Exothermic vs. Endothermic Changes Exothermic Change: A + B → C + D + energy Exothermic Change: A + B → C + D + energy Energy is released or “ex”its Energy is released or “ex”its Endothermic Change: A + B + energy → C + D Endothermic Change: A + B + energy → C + D Energy is absorbed or “en”ters Energy is absorbed or “en”ters

20. Energy During Phase Changes Endothermic: (s→l, or l→g) Endothermic: (s→l, or l→g) Energy overcomes attractive forces between particles Energy overcomes attractive forces between particles PE increases PE increases Exothermic: (g→l, or l→s) Exothermic: (g→l, or l→s) As particles come closer together energy is released As particles come closer together energy is released PE decreases PE decreases

21. Heating & Cooling Curves Graphically represents temp. changes as heat energy is added or taken away. Graphically represents temp. changes as heat energy is added or taken away.

22. Label This Graph

23. Interpreting the Graph The slanted portions = temp is changing The slanted portions = temp is changing Single phase is heating up or cooling down Single phase is heating up or cooling down KE is changing KE is changing The flat portions = temp not changing The flat portions = temp not changing Substance undergoing a phase change PE is changing

24. Heating Curve for Water

25. What is Melting Pt? Boiling Pt?

26. Heat Equations Calculates the energy involved when a substance changes in temperature or undergoes a phase change. Calculates the energy involved when a substance changes in temperature or undergoes a phase change.

27. Physical Constants for Water Table B Use these constants in Heat Equations H f = heat of fusion = 334J/g H v = heat of vaporization = 2260J/g Specific Heat Capacity (“c”) = 4.18 J/g x K

28. When temperature of substance changes use this formula: When temperature of substance changes use this formula:

29. What is Specific Heat Capacity? Specific Heat: “c” Joules of heat needed to raise 1 gram of a substance 1°C. Substances have different abilities to absorb heat when energy is applied depending on their composition. Substances have different abilities to absorb heat when energy is applied depending on their composition. Ex: Piece of Iron vs. Water.

30. When Undergoing Phase Change use one of these formulas: TEMPERATURE CONSTANT When Undergoing Phase Change use one of these formulas: TEMPERATURE CONSTANT Q = mHf Use when changing from solid to liquid (melting) or liquid to solid (freezing) Q = mHf Use when changing from solid to liquid (melting) or liquid to solid (freezing) Q = mHv Use when changing from liquid to gas (vaporization) or gas to liquid (condensing) Q = mHv Use when changing from liquid to gas (vaporization) or gas to liquid (condensing)

31. Calorimeters Instrument used to determine amount of heat lost or gained in a reaction by measuring changes in the temp. of water surrounding the system. Instrument used to determine amount of heat lost or gained in a reaction by measuring changes in the temp. of water surrounding the system. Q = mcΔT Virtual Calorimetry http://group.chem.iastate.edu/G reenbowe/sections/projectfolder /flashfiles/thermochem/heat_me tal.html

32. Try This!! Online App Demonstrates Specific Heat and Calorimetry Online App Demonstrates Specific Heat and Calorimetry http://elearning.classof1.com/demo/2D_Lab/Chemistry/specificHeat/ specificHeat.html http://elearning.classof1.com/demo/2D_Lab/Chemistry/specificHeat/ specificHeat.html http://elearning.classof1.com/demo/2D_Lab/Chemistry/specificHeat/ specificHeat.html http://elearning.classof1.com/demo/2D_Lab/Chemistry/specificHeat/ specificHeat.html

33. Multi-step Heat Problems (Honors) Need to use more than one of the heat equations and add up the total heat. Need to use more than one of the heat equations and add up the total heat. Note: Specific Heat of different phases of water! Note: Specific Heat of different phases of water! H 2 O(s) = 2.10 J/g x °C H 2 O(s) = 2.10 J/g x °C H 2 O (l) = 4.18 J/g x °C H 2 O (l) = 4.18 J/g x °C H 2 O(g) = 1.84 J/g x °C H 2 O(g) = 1.84 J/g x °C Ex: Calculate the heat energy to raise 10 grams of water at -25°C to 80°C. Ex: Calculate the heat energy to raise 10 grams of water at -25°C to 80°C. Draw a heating curve. Figure out # of steps. Draw a heating curve. Figure out # of steps. 1.) Heat ice from -25° to 0°q = mcΔT 1.) Heat ice from -25° to 0°q = mcΔT 2.) Melt ice to liquid at 0°q = mHf 2.) Melt ice to liquid at 0°q = mHf 3.) Heat liquid water from 0° to 80° q = mcΔT 3.) Heat liquid water from 0° to 80° q = mcΔT

34. Heat Lost = Heat Gained (Honors) When two objects of different temperatures are placed together in a closed system, heat flows from hotter to colder object until they reach same temperature. When two objects of different temperatures are placed together in a closed system, heat flows from hotter to colder object until they reach same temperature. mcΔT = mcΔT Total heat lost = total heat gained Total heat lost = total heat gained