Particle model of matter

• Solids

  regular lattice structure

  Strong forces of attraction

  vibrate in a fixed position

  have fixed size and shape
• Liquids

  Weak forces of attraction

  have fixed volume but can change shape

  irregular structure
• Gases

  Very weak forces of attraction

  Free to move

  random arrangement

  can change volume and shape
• Heating gas

  Flexible container = volume increase

  fixed container = pressure increase
• Density

  solids are most dense

  liquids have a lower density

  gases have the lowest density
• Density equation

  Density = mass divided by volume
• Density RP (solids)


  Mass = weigh on a mass balance

  volume = regular : length x width x height or if it’s irregular: use eureka can filled with water then add the the solid being tested and measure the water displaced this equals the volume of the solid
• Density RP (liquids)

  Mass = empty beaker and switch mass balance to zero then add liquid

  volume = equal to mass so 10ml is equal to 10cm3

  (larger volume = more accurate density as it minimises uncertainty)
• Specific latent heat

  Energy required to change 1kg of a particular substance form one state to another without changing the temperature (heating)

  amount of energy released when changing state (cooling)
• Specific latent heat

  vaporisation = energy change when a substance changes between liquid and gas

  fusion = energy change when a substance changes between a solid and a liquid
• Specific latent heat equation

  Energy required/released = mass x specific latent heat
• Gas pressure

  Pressure = force/area

  Depends on number of collisions and energy of each collision
• Factors on gas pressure

  Temp = increase kinetic energy so more frequent collisions with more force = increase in pressure

  concentration = increase concentration means more frequent collisions as more particles = increase pressure

  volume = decrease volume is similar to increase

  concentration so more frequent collisions = increase pressure
• Flexible container

  If container is flexible temperature concentration it will increase volume and eventually pressure as it can only expand so much
• Pressure and volume

  Are inversely proportional

  pressure x volume = constant