1. Phases of Matter

2. Kinetic Theory
All matter is made of atoms and molecules that act like tiny particles.
These tiny particles are always in motion. The higher the temp., the faster the particles move.
At the same temp., more massive (heavier) particles move slower than less massive (lighter) particles.

3. SOLIDS Definite shape? YES Definite volume?
Molecules in a solid are tightly packed and constantly vibrating.

4. LIQUIDS Definite shape? NO Definite volume? YES
Some liquids flow more easily than others. The resistance of a liquid to flow is called viscosity.
Honey has a high viscosity compared to water.

5. GASES Definite shape? NO Definite volume?
The particles in a gas are spread very far apart, but can be compressed by pumping them into a restricted volume.

6. Phase Changes Changes in phase are examples of physical changes.
Melting: solid  liquid
Freezing: liquid  solid
Vaporization: liquid  gas
Condensation: gas  liquid
Sublimation: solid  gas

7. Changes of State SOLID GAS LIQUID Melting Vaporization Condensation
Deposition
Sublimation
Vaporization
Condensation
Melting
Freezing
LIQUID

8. ENERGY TRANSFERS!!! ENERGY is the ability to change or move matter.
Energy is ABSORBED when substances melt or evaporate.
NOTE: our bodies cool down when our sweat evaporates.
Energy is RELEASED when substances freeze or condense.

9. Melting The change of state from solid to liquid.
Energy (heat) is absorbed by the substance that is melting.

10. Freezing
The change of state from liquid to solid. Opposite of melting. Energy (heat) is released by the substance undergoing freezing.

11. Evaporation
Evaporation: the process in which molecules escape from the surface of a liquid; can happen at any temperature, but occurs more rapidly as temperature increases.

12. Boiling Change from state from a liquid to a gas.
Occurs throughout the liquid.
boiling point/temperature is determined by pressure
Energy (heat) is absorbed by the liquid.

13. Boiling
A rapid state of evaporation that takes place within the liquid as well as at it’s surface. Like evaporation, cooling of the liquid results.
Boiling point: the temperature at which the vapor pressure of the liquid equals the ambient (surrounding) pressure.
***the normal boiling pt = the temp at which a liquid’s vapor pressure = 760 mm Hg or 1 atm

14. Vaporization (evaporation and boiling)
vapor pressure: the pressure exerted by the vapor of the liquid on its surface at equilibrium in a closed container; increases as temperature increases
***liquids with high boiling points have low vapor pressures and relatively strong intermolecular attractions.

15. Condensation
The change of state from gas to liquid. The opposite of evaporation.
Energy (heat) is released by the liquid (Warming of the liquid results)

16. Sublimation

17. Deposition

18. Phase Change Graph
*Boiling & freezing points depend on the pressure.

19. Water at normal pressure (1 atm):
For water at normal (every day) pressures:
Melting/freezing point:
Condensing/boiling point:
0 oC (32oF)
100 oC (212oF)
Label the points & temperatures on your graph.

20. Change the pressure  Change the Boiling Point

21. Phase Diagrams
a phase diagram shows the equilibria pressure-temperature relationship among the different phases of a given substance

22. WATER
Carbon Dioxide C
AD =
AB =
AC =

23. C
melting curve
AD =
AB =
AC =

24. C
melting curve
sublimation curve
AD =
AB =
AC =

25. C
vapor pressure curve
melting curve
sublimation curve
AD =
AB =
AC =

26. A D triple point = Point ______C A
triple point = Point ______
The point at which all 3 phases of a substance (solid, liquid, gas) can coexist at equilibrium. D
critical point = Point ______
The combination of critical temperature and critical pressure.
critical temp = temp. above which a gas cannot be liquefied. (H2O=374ºC)
critical pressure = press. required to liquefy a gas at its critical temperature. (H2O=218 atm)

27. Conditions for H2O on other planets…