1. The Nature of Matter Mr. Gilbertson Chemistry Chapter 3 Solids, Liquids, and Gases

2. Matter Has Mass Has Mass Takes up Space (Volume) Takes up Space (Volume) Exhibits the property of Inertia Exhibits the property of Inertia States of matter States of matter  Solid – definite volume, definite shape  Liquid – definite volume, no definite shape  Gas – no definite volume, no definite shape  Plasma – like gas, exists only at very high temperatures or of very high energy particles

3. State of Matter Depends on the temperature (ultimately the average internal Kinetic energy of motion of the particles. Depends on the temperature (ultimately the average internal Kinetic energy of motion of the particles. Crystalline substances undergo phase changes at specific temperatures (water, steel, lead, etc.). Crystalline substances undergo phase changes at specific temperatures (water, steel, lead, etc.).  Melting/Freezing Point – transition temperature between solid and liquid.  Boiling Point – temperature at which a liquid changes rapidly to a gas. Amorphous substances have no definite transition temperatures (wax, butter, glass, etc.). Amorphous substances have no definite transition temperatures (wax, butter, glass, etc.).

4. States of Matter

5. Solids Has a definite volume - can’t be compressed. Has a definite volume - can’t be compressed. Has a definite shape - can’t be changed without the application of force. Has a definite shape - can’t be changed without the application of force. Classification: Classification:  Crystalline – particles are arranged in a repeating geometric pattern (crystal).  Amorphous (Noncrystalline) – particles are said to “have no form”, many may be thought of as thick liquids. Particles are close together and unable to move past one another, though they do vibrate in place. Particles are close together and unable to move past one another, though they do vibrate in place.

6. Solids - Crystalline

7. Arrangement of particles in a solid – the crystalline lattice

8. Liquids No definite shape – takes the shape of its container. No definite shape – takes the shape of its container. Has a definite volume – like solids can’t be compressed. Has a definite volume – like solids can’t be compressed. Particles in a liquid. Particles in a liquid.  have greater energy and therefore faster motion than those of solids.  are spaced further apart than in solids, thus allowing particles to move past one another, this explains why liquids can flow.  are attracted to each other and so they do stick together.

9. Gases No definite shape – like liquids they take the shape of their container (“springy”). No definite shape – like liquids they take the shape of their container (“springy”). No definite volume – with the application of a force they can be compressed. No definite volume – with the application of a force they can be compressed. Particles of a gas: Particles of a gas:  Have a large amount of energy and are able to separate completely.  Have relatively low attraction for each other so they can expand and be compressed easily.

10. Plasma Like a gas, No definite volume, No definite shape. Like a gas, No definite volume, No definite shape. Exists only at very high temperatures or of very high energy particles. Exists only at very high temperatures or of very high energy particles. Particles are charged both positive and negative (protons and electrons) Atoms can’t maintain integrity. Particles are charged both positive and negative (protons and electrons) Atoms can’t maintain integrity. Form in which matter of sun and stars exists, also found in fluorescent lights. Form in which matter of sun and stars exists, also found in fluorescent lights.

11. Plasmas

12. Kinetic Theory of Matter All matter is composed of particles (atoms or molecules). All matter is composed of particles (atoms or molecules). All particles are in motion (vibration). All particles are in motion (vibration). Motion is directly proportional to the temperature. As temperature increases so does the motion of the particles. Motion is directly proportional to the temperature. As temperature increases so does the motion of the particles. At absolute zero there is no motion (0.0 K or –273 o C). At absolute zero there is no motion (0.0 K or –273 o C).

13. Particle Spacing As the phase changes, the average distance between the particles increases. In solids the particles vibrate within a crystalline lattice. In liquids the particles move to a distance equal to one diameter of the particle or more, attractive forces are still strong. In gases the particles move far enough apart to overcome all attraction between particles.

14. Molecular Forces

15. Thermal Expansion The general increase in volume as a result of an increase in temperature. Change in volume is said to be directly proportional to the change in temperature. The general increase in volume as a result of an increase in temperature. Change in volume is said to be directly proportional to the change in temperature. Matter also tends to contract as a result of temperature changes. Matter also tends to contract as a result of temperature changes. Explained by Kinetic Theory of Matter. Explained by Kinetic Theory of Matter.  When heated the particles move faster so they push harder against one another and so they move apart in all directions.  A thermometer demonstrates this property.

16. Thermal Expansion An expansion joint is often inserted into roads and bridges to prevent damage when the temperatures change. Space must be left between the railroad track sections for the same reason.

17. Thermal Expansion The fact that materials expand and contract predictably when heated or cooled allows us to make thermostats using bimetallic strips. Bimetallic strips use two metals bonded to each other, since each has a different coefficient of expansion one side expands more than the other when heated. This causes the strip to bend, this fact can be used to open or close a circuit to activate a heating or cooling system.

18. Changes in State Evaporation – change from a liquid to a vapor at temperatures below boiling point, often used to cause cooling. Evaporation – change from a liquid to a vapor at temperatures below boiling point, often used to cause cooling. Sublimation – change from a solid to a gas without passing through the liquid state. Sublimation – change from a solid to a gas without passing through the liquid state. Condensation – the change from a gas to a liquid at temperatures below the boiling point. Condensation – the change from a gas to a liquid at temperatures below the boiling point.

19. Evaporation Particles of a liquid will continue to evaporate until the pressure exerted by the particles leaving is equal to the pressure of the atmosphere, at which time the particles will condense at the same rate as they evaporate. This is known as equilibrium.

20. Condensation Occurs when water vapor is cooled below its boiling point, as altitude increases boiling point decreases.

21. Distillation - using phase changes

22. Phase Changes The phase of matter is dictated by the temperature and the pressure conditions. The graph above shows the temperature and pressure conditions necessary to cause a phase change. The lines represent transitions, above the critical point it is impossible to distinguish between a liquid and a gas. The triple point is the temperature and pressure conditions necessary to exist in all three states simultaneously. Triple point DemoTriple point Demo

23. Heat and State Changes Heat of fusion – The amount of heat energy which is necessary to change a solid to a liquid or vice versa. (for water 334 kJ/kg). Heat of fusion – The amount of heat energy which is necessary to change a solid to a liquid or vice versa. (for water 334 kJ/kg).  Heat must be absorbed to melt, must be lost to freeze. Heat of vaporization – The amount of heat energy which is necessary to change a liquid to a gas or vice versa. (for water 2260 kJ/kg). Heat of vaporization – The amount of heat energy which is necessary to change a liquid to a gas or vice versa. (for water 2260 kJ/kg).  Heat must be absorbed to vaporize, heat must be lost to condense.

24. As a sample of ice is warmed and the temperature is measured every 30 seconds, the particles of solid water absorb the applied heat energy.

25. As heat energy continues to be supplied, you may notice that the solid water now begins to appear as a liquid, but the temperature is not rising. To change a solid to a liquid, many forces must be overcome, the energy is known as the heat of fusion.

26. Once the work of melting is accomplished, the applied heat energy causes the water particles making up the liquid to move faster. As you can see from the graph, the temperature begins to rise.

27. Once the boiling has been reached, the liquid becomes a gas, and the temperature again remains constant, At the heat of vaporization, the forces of attraction between particles are totally overcome. This requires 2260kJ of energy.

28. Video about chemical and physical changes Physical and Chemical Changes

29. THE END