Chapter 6 Section 2- changes of state
Kinetic and Potential Energy Kinetic energy- the energy of motion faster the particles move then the greater the KE Gases have the greatest KE, particles are moving the fastest in this state of matter Temperature- the average KE of all the particles in the object Potential energy- stored energy PE increases when objects are farther apart and decreases when objects get closer Chemical PE is due to the positions particles relative to other particles Gases have the most PE
Thermal energy The total potential and kinetic energies of an object Can change a state of matter by increasing or decreasing the thermal energy of the object
Solid to liquid or liquid to solid Melting- S to L- thermal energy added Thermal energy and temperature increase until the melting point. At this point the temperature does not change but the PE is increasing (particles are moving farther apart) Freezing is the reverse of melting
Liquid to Gas or Gas to Liquid Liquid to gas- vaporization Vaporization within a liquid is called boiling KE of the particles increases until it reaches the boiling point Then temperature remains the same but the potential energy changes Evaporation- occurs on the surface of a liquid Condensation- the reverse process- if a gas loses enough thermal energy it will become a liquid
Solid to gas or gas to solid Sometimes the intermediate state is not necessary Dry ice- solid carbon dioxide changes to a gas with no liquid state This is called sublimation Deposition- going from gas to solid with no liquid state Frost on the grass
Conservation of mass and Energy Two famous laws Matter can neither be created nor destroyed Matter can change form or state but you are not losing anything or gaining anything