STATES OF MATTER CHAPTER 3

SOLIDS, LIQUIDS, AND GASES 3.1

STATES OF MATER Materials can be classified as solids, liquids or gases based on: shape and whether volume is define or variable

SOLIDS Define shape Define volume Atoms are close together Very limited movement of atoms Ordered arrangment

LIQUIDS Definite volume No definite shape-takes the shape of its container, can be moved from one container to another Atoms are arranged more randomly More particle movement

GASES No definite shape No definite volume Takes shape and volume of container Atoms are random Lots of particle movement

PLASMA Most common state of matter in the UNIVERSE 99% of matter does not exist as a solid, liquid or gas Exists at high temps

BOSE-EINSTEIN CONDENSTATE Matter that exists at very low temperatures (-273 C) Atoms behavior as if they are one particle

KINETIC THEORY Kinetic energy: energy of moving objects The kinetic theory of matter says that all particles of matter are in constant motion

BEHAVIOR OF GASES Gases move like billiard balls Will move in a straight line until one ball hits another and its motion is changed seconds

BEHAVIOR OF GASES Forces of attraction exist between all particles of matter In solids they are stronger because movement is slower In gases the attractions don’t matter because gases move to fast

BEHAVIOR OR GASES Kinetic Theory of Gases: constant motion of gas particles allows it to fill a container of any shape and size

KINETIC THEORY OF GASES 1.Particles in gas are in constant, random motion 2.Motion of one particle is unaffected by the motion of other particles (unless particles collide) 3.Forces of attraction among particles in a gas can be ignored under ordinary conditions

EXPLAINING BEHAVIOR OF LIQUIDS Liquid takes the shape of its container because particles in a liquid can move to new spots Volume of a liquid is always the same because forces of attraction keep particles close to together (particles don’t move fast enough to overcome them)

BEHAVIOR OF SOLIDS Definite volume and shape because particles vibrate around fixed spots Attraction forces are very strong, seems like one solid piece GLASS

THE GAS LAWS 3.2

PRESSURE Pressure: result of a force distributed over an area Smaller the area, higher the pressure if applied with same force SI Unit = 1 pascal = 1 N/m 2 Collisions of gas particles and walls of the container cause pressure in a closed container of gas

FACTORS AFFECTING GAS PRESSURE Temperature = raising temperature increases pressure if volume and number of gas particles are constant because it increases kinetic energy Volume = reducing volume increases pressure if the temperature of the gas and the number of particles are the same, less space means that gas particles will collide more with the wall Number of Particles = increases the pressure of a gas if the temp and volume are the same because the number of collisions of gas particles on the container wall increases

CHARLES LAW Volume of a gas is proportional to its temp (K) if pressure and number of particles are the same V 1 V 2 T 1 T 2 Absolute Zero = temperature (K) where minimum movement of particles is zero, gas has volume of 0 L

CHARLES LAW

BOYLES LAW Volume of gas is inversely proportional to its pressure if temperature and number of particles are the same If you increase volume, pressure decreases If you increase pressure, volume decreases P 1 V 1 = P 2 V 2

COMBINED GAS LAW Relates temperature, volume and pressure if number of particles stays the same. P 1 V 1 P 2 V 2 T 1 T 2

PHASE CHANGES 3.3

PHASE CHANGES Phase change = reversible physical change that occurs when a substance changes from one state of matter to another

PHASE CHANGES Temperature of a substance does not change during a phase change

PHASE CHANGES Energy is either absorbed or released during a phase change Endothermic = absorbs energy from surroundings (temp of substance usually rises) Exothermic = release energy from surroundings (temp of substance usually cools)

MELTING AND FREEZING The arrangement of molecules become less orderly as a substance melts and more orderly as it freezes Melting: Endothermic, Energy Increases in substance At the melting point some molecules get enough energy to overcome forces of attraction in solids to become a liquid, is it gets warmer and warmer more molecules will do this Freezing: Exothermic, Energy decreases in substance At the freezing point particle motion slows down in the liquid and the forces of attraction have a larder effect and pull the molecules into and orderly arrangement

MELTING AND FREEZING

VAPORIZATION AND CONDENSATION Vaporization: Endothermic, liquid  gas, energy increases Evaporation: changes a liquid to a gas below the substances boiling point (vaporization a the surface) Condensation: Exothermic, gas  liquid, energy decreases Boiling Point Depends on Atmospheric pressure

SUBLIMATION AND DEPOSITION Sublimation: Endothermic, solid  gas, energy increases Ex: Dry Ice Deposition: Exothermic, gas  solid, energy decreases Ex: frost on window