topic 14 particle model

• kinetic theory

  • kinetic theory states that everything is made up of tiny particles
  • the way the particles are arranged vary in solids , liquids and gases
• kinetic theory

  • kinetic theory states that everything is made up of tiny particles
  • the way the particles are arranged vary in solids , liquids and gases
• solids

  • forces of attraction hold the particles together
  • the particles can vibrate but cannot move around
  • solids keep their shape and cannot be compressed
• Liquids

  • move faster so the forces of attraction between the particles are not strong enough to hold in fixed position
  • particles can move past eachother
  • liquids flow and take the shape of a container
• Gas

  • particles move quickly and are far apart
  • gas can be compressed and expand to fill containers
• conservation of mass : mass is not gained or lost as the number of particles stay the same
• melting - solid to liquid

  freezing - liquid to solid

  evaporating / boiling - liquid to gas

  condense - gas to liquid

  sublime - solid to gas
• density : the density of a substance is the mass of a certain volume of a substance

  density = mass / volume
• exception to density rule

  • water freezes - particles are spread out
  • ice is the least dense
• factors affecting pressure

  • particle concentration
  • volume
  • temperature
• particle concentration

  • high pressure - there are more particles colliding with the walls of a container
  • low pressure - there are less particles colliding with the wall of a container
• container volume

  • larger container - larger volume , same particle concentration , less collisions with container wall , low pressure
  • smaller container - smaller volume , same particle concentration , more collisions with container walls , high pressure
• temperature - pressure

  • low temperature - low pressure
  • high temperature - high pressure
  • high temperature - particles move faster , have more kinetic energy
• absolute zero

  • -273 C
  • 0 k
  • particles have no kinetic energy - will not move
  • particles will not be exerting any pressure
• investigating densities of liquid

  1. measure mass of empty measuring cylinder
  2. pour known volume of liquid , re-weigh cylinder
  3. calculate mass of liquid on its own
  4. calculate density
• investigating density of regular shaped solids

  1. measure with ruler dimension of object
  2. calculate volume
  3. weigh mass of solid
  4. calculate density
• investigating density of irregular shaped objects

  1. measure mass of object
  2. fill eureka can with water till the spout
  3. place can on top of tripod and measuring cylinder under the spout
  4. lower object into eureka can
  5. water displaced = volume of water
  6. calculate density
• specific latent heat : the amount of energy that is taken in or given out in order to make 1kg of substance to change state

  • Q = mL
  • Q = energy (J )
  • m = mass ( kg )
  • L = latent heat ( J/kg)
• specific heat capacity : the amount of energy required to increase the temperature of 1kg of a substance by 1 C

  • Q = m x c x t
  • Q - change in energy ( J )
  • m - mass ( kg )
  • c - specific heat capacity ( J/kg C )
  • t - change in temperature ( c )
• calculations involving temperature , volume and pressure

  • P1 x V1 / T1 = P2 x V2 / T2
  • P1 - starting pressure
  • V1 - starting volume
  • T1 - starting temperature
  • P2 - finishing pressure
  • V2 - finishing volume
  • T2 - finishing temperature
  • Volume - m^2
  • pressure - pascals (Pa)
  • temperature - K ( kelvin )