P3

• • Density is defined as the mass per unit volume

  $density =$$mass / volume$

  • density of an objects depends on what it is made of + how particles are arranged
  • solids - strong forces of attraction , vibrate in fixed position, high density
  • liquid - weaker forced of attraction , irregular arrangement + random moves, less dense
  • Gas - travel at high speed, low densities
• Internal energy is the energy stored by the particles making up a system

  internal energy = kinetic energy + potential energy of all substances

  increase in temp = particles gain kinetic energy

  constant temp = particles gain potential energy

  specific latent heat = energy required to change the state of 1kg of a substance
• gas pressure: result of particles colliding with the walls of its container, exerting a force outwards

  the higher the temperature, the greater the kinetic energy so the faster the averages speed of molecules