particle model of matter

• density = mass / volume
• when particles are packed tightly they have a high density
• particles can be arranged in different ways to form solids, liquids or gases
• solids are usually more dense than liquids and gases
• gases are less dense than liquids
• eureka can

  A) density practical

  
• changes of state

  
• the internal energy of a system is the total energy of potential and kinetic energy stores
• heating the system means kinetic stores will move faster as they gain energy
• a change will occur if the substance is heated enough, if enough energy is supplied to break the bonds
• solids have strong forces of attraction
• when gases collide with a container they exert force
• an increase in temperature increases the speed of the particles so they collide more frequently
• larger momentum = larger force exerted when colliding
• internal energy increases

  
• internal energy decreases

  
• specific latent heat is the amount of energy needed to change the state of 1kg mass without changing temp
• specific latent heat of fusion is the amount of energy needed to change the state of 1kg of a substance from solid to liquid
• specific latent heat of vapourization is the amount of energy needed to change 1kg of a substance from a liquid to a gas
• energy = mass x specific latent heat