4 Discuss and evaluate the 5th state of matter. 3 - Differentiate among the four states of matter in terms of energy,

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1 Goal: Differentiate among the four states of matter in terms of energy, particle motion, and phase transitions. 4 States of Mater Sections 3.1, Discuss and evaluate the 5 th state of matter. 3 - Differentiate among the four states of matter in terms of energy, particle motion, and phase transitions. 2 Explain the 6 phase transitions. 1 Recognize the four states of matter. Learning Objectives 1. Describe the 4 states of matter. 2. Classify materials as solids, liquids, or gases 3. Explain the behavior of gases, liquids, and solids, using kinetic theory. 4. Describe phase changes. 5. Explain how temperature can be used to recognize a phase change. 6. Explain what happens to the motion, arrangement, and average kinetic energy of water molecules during phase changes. 7. Describe each of the six phase changes. 8. Identify phase changes as endothermic or exothermic. How Shape & Volume Classifies Materials Materials can be classified as solids, liquids, gases, or plasmas based on whether their shapes and volume are definite or variable Definition: a solidis the state in which materials have a definite shape and definite volume Definition: definite means that shape and volume won t change unless the material is acted on by an outside force How Shape & Volume Classifies Materials Definition: a liquidis the state of matter in which material has a definite volume but not a definite shape Liquids will take the shape of their container Definition: a gas is the state of matter in which a material has no definite shape and no definite volume Gases will expand to completely fill the volume & take the shape of their container 4 states of matter Almost all matter exists as a solid, liquid or gas on Earth This is not true for the universe In places with the temperature of stars, matter exists in a state called plasma In 1995, scientists discovered a fifth state of matter called BCE (Bose-Einstein condensate) At temperatures close to absolute zero (0 K or -273ºC), BCE groups of atoms behave as if they were a single particle 1

2 Kinetic Theory Definition: kinetic energy is the energy an object has due to its motion Kinetic theory says: 1. That all particles of matter are in constant motion 2. There are forces of attraction among all particles of matter Kinetic Theory of Gases 1. The constant motion of particles in a gas allows a gas to fill a container of any shape or size 2. Particles in a gas are in constant, rapid, random motion 3. The motion of 1 particle of gas is unaffected by other particles of gas unless they collide 4. Forces of attraction among particles of gas can be ignored under ordinary conditions Kinetic Theory of Liquids 1. A liquid takes the shape of its container because particles in a liquid can flow to new locations 2. The volume of a liquid is constant because forces of attraction keep particles close together Kinetic Theory of solids 1. Solids have a definite shape and volume because particles in a solid vibrate about a fixed point Six Common s Definition: a phase change is the reversible physical change that occurs when a substance changes from one state of matter to another Six common phase changes: melting, freezing, vaporization, condensation, sublimation, and deposition PHASE CHANGES Description of Solid to liquid Liquid to solid Term for Phase Change Melting Freezing Heat Movement During Heat goes into the solid as it melts. Heat leaves the liquid as it freezes. 2

3 PHASE CHANGES Description of Liquid to gas Term for Phase Change Heat Movement During Vaporization, which includes Heat goes into the boiling and liquid as it vaporizes. evaporation Gas to liquid Condensation Solid to gas Sublimation Heat leaves the gas as it condenses. Heat goes into the solid as it sublimates. Temperature, Energy & Phase Changes The temperature of a substance does not change during a phase change For example, water temperature remains constant when boiling to go from liquid to gas or when condensing from a gas to liquid Q: At what temperature does water boil and condense? A: Temperature, Energy & s Exothermic vs. Endothermic Changes Energy is either absorbed or transferred during a phase change The amount of energy absorbed depends on the substance & is a unique physical property for each substance Definition: heat of fusion is the amount of energy absorbed when going from a solid to a liquid Definition: exothermic changes occur when energy is released to the environment An example of an exothermic change is water freezing since it releases its heat to the environment so that it can freeze Definition: endothermic changes occur when energy is absorbed from the environment An example is water melting since it gathers as much heat as possible from the environment to melt Melting & Freezing Water The arrangement of molecules in water becomes less orderly as water melts and more orderly as water freezes Solid water (ice) has molecules in a fixed position that vibrate about a fixed point Freezing produces molecules in an orderly arrangement Liquid water has molecules that are attracted to each other and slide past each other due to special chemical bonds Melting allows a less orderly molecular arrangement Evaporation & Boiling Definition: vaporization is a phase change from a liquid to a gas Vaporization is endothermic since liquid water absorbs energy in the form of heat from the surroundings to go from liquid to gas Definition: heat of vaporization is the amount of energy needed for a substance to change phases from liquid to gas Heat of vaporization is a unique physical property for each substance 3

4 Evaporation & Boiling Boiling Point and Condensation Definition: evaporation is the process that changes a substance from a liquid to a gas below the substance s boiling point Evaporation is a process that takes place at the surface of a liquid and occurs at temperatures below the boiling point Definition: vapor pressure is the pressure caused by the collisions of vapor on the walls of the container Vapor pressure increases as temperature increases Q: How does surface area of a liquid affect the rate of evaporation? Definition: the boiling point is where vapor pressure equals atmospheric pressure Kinetic theory shows that as the temperature increases, water molecules move faster & faster until they have energy to overcome attractive forces of neighboring molecules Definition: condensationis the phase change from a gas or vapor to a liquid Sublimation/Deposition Definition: sublimation is the phase change from solid to a gas without going through the liquid phase Example of sublimation is dry ice to CO2 at room temperature Definition: deposition is the phase change from a gas or vapor to a solid without going through the liquid phase Deposition is the reverse of sublimation Example of deposition is frost on windows But what happens if you raise the temperature to super-high levels between 1000 C and 1,000,000,000 C? Will everything just be a gas? STATES OF MATTER PLASMA A plasma is an ionized gas. A plasma is a very good conductor of electricity and is affected by magnetic fields. Plasmas, like gases have an indefinite shape and an indefinite volume. Plasma is the common state of matter STATES OF MATTER SOLID LIQUID GAS PLASMA Tightly packed, in a Close together with Well separated with regular pattern no regular no regular Has no definite Vibrate, but do not arrangement. arrangement. volume or shape move from place to Vibrate, move Vibrate and move and is composed of electrical charged place about, and slide freely at high particles past each other speeds 4

5 Some places where plasmas are found 1. Flames 2. Lightning 3. Aurora (Northern Lights) The Sun is an example of a star in its plasma state 5