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 .