MATTER • Affected by temperature and pressure • A change in temperature and/or pressure can change the state of matter of a substance
Kinetic Theory:how particles in matter behave Three assumptions 1. All matter is made of small particles - atoms, molecules and ions 2. These particles are in constant motion. The motion has no pattern. 3. These particles are colliding or crashing into each other and into the walls of their container.
Thermal Energy • Thermal energy is the total energy of the particles in a material. • Thermal energy includes kinetic energy and potential energy • Solid particles do not appear to be moving but they are! Solid particles move slowly.
Absorb or ReleaseThermal Energy • When particles absorb thermal energy then • Temperature increases or • Temperature remains constant and particles transition to moreenergetic phase of matter • When particles release thermal energy then • Temperature decreases or • Temperature remains constant and particles transition to lessenergetic phase of matter
Temperature • Measure of the average kinetic energy of the vibrating or moving atoms or molecules of a substance • Absolute zero= no movement • Heat= the total kinetic energy of a substance
Pressure These gas molecules are constantly moving in random directions. When a molecule hits the container wall (green), it exerts a tiny force on the wall. The sum of these tiny forces, divided by the interior surface area of the container, is the pressure. the force per unit area applied on a surface in a perpendicular direction
One atmosphere is defined as the pressure caused by the weight of all the overlying air at sea levelor 14.7 pounds per square inch (psi).
Solid http://www.chem.purdue.edu/gchelp/liquids/character.html http://www.chem4kids.com/files/matter_solid.html • Low Temperature and/or High Pressure • Low Kinetic energy • Definite pattern resulting in definite volume and definite shape • Can be an atom, ion or molecule • Usually in crystalline form, although some are glass
Liquid http://www.chem.purdue.edu/gchelp/liquids/character.html http://www.mcwdn.org/chemist/liquids.html • Less Pressure, More Kinetic Energy • Definite volume, no definite shape • Melting point= the vibrations of the particles cause the forces holding the solid together to break • These forces are called attractive forces.
Gas http://www.chem.purdue.edu/gchelp/liquids/character.html http://www.mcwdn.org/chemist/gases.html • Least pressure, most kinetic energy • No definite shape, no definite volume • Evaporation is the boiling point of the liquid • Gravity – prevents escape of gases • Gas would escape to space if not for the Earth’s gravity
Plasma • Hot ionized temperatures above 5000°C • Violent collisions cause electrons to be knocked off • Stars, lightning, neon signs, solar wind, auroras, comet tails, welding arcs, fireball made by nuclear weapons http://dewa.com/animated/ http://en.wikipedia.org/wiki/Plasma_(physics)
Condensation • Change in matter to … a denser stage through colder temperatures or more pressure • Gas phase to a liquid phase http://en.wikipedia.org/wiki/Condensation http://en.wikipedia.org/wiki/Condensation http://ga.water.usgs.gov/edu/watercyclecondensation.html
Sublimation • Skip a Phase: Solid-->Gas • Carbon dioxide (dry ice), Naphthelene (moth balls) and snow sublime http://ga.water.usgs.gov/edu/watercyclesublimation.html http://ga.water.usgs.gov/edu/watercyclesublimation.html http://www.windows.ucar.edu/tour/link=/comets/sublimation.html&edu=high
Conservation of Matter and Energy • During an ordinary chemical change, there is no detectable increase or decrease in the quantity of matter. LAW • Energy cannot be created or destroyed, it can only change its form. http://dewa.com/animated/
gas liquid releases liquid solid releases solid liquid absorbs absorbs liquid gas absorbs solid gas
Recap of Phase Changes • Melting – Solid to • Freezing – Liquid to • Evaporation – Liquid to • Condensation – Gas to • Sublimation – Solid to