kinetic theory
3 Types of States
solid , liquid and gases - the particles are arranged together , its tightly packed together and vibrate around fixed positions .
liquid - particles are close together but is able to slide past each other
gas - particles in gas are far apart and can move quickly and randomly
increasing energy is from solid - liquid - gas
increasing density is from gas- liquid- solid
solid - fixed shape , fixed volume, cannot be compressed , also have high density
State changes
solid becomes liquid - melting
liquid becomes gas - evaporation
gases become liquids - condensation
liquids become solids - freezing
Melting
requires heat energy which transform to kinetic energy .
Freezing
this is reverse of melting and occurs at exactly the same temperature as melting point. ex - water freezes and melts at 0 degree c
Boiling
requires heat which causes bubbles of gas to form below the surface and within the liquid .
Evaporation
gas occurs over a range of temperatures , evaporation occurs only at surface of the liquids where high energy particles can escape from liquid surface at low temp
Condensation
liquid on cooling and takes place over a range of temp . when gas is cooled its particles loose energy . when they bump into each other they lack energy to bounce away again , they group together to form liquid
Pressure And Temperature in Gases
a change in temp or pressure affects the volume of gas
as air inside a hot air balloon is heated up, it expands and balloon gets bigger
this is because the volume of gas increases as temp increases .