Particle Model of Matter

• how do you calculate density?

  mass(kg)/volume
• what is the arrangement of particles in solids?

  • strong forces of attraction hold the particles close together in a fixed, regular arrangement
  • particles do not have a lot of energy so they can only vibrate about their fixed positions - high density
• what is the arrangement of particles in liquids?

  • there are weaker forces of attraction between the particles
  • particles are close together but can move past each other and form irregular arrangement
  • have more energy than particles in a solid - move in random directions at low speeds
  • generally less dense than solids
• what is the arrangement of particles in a gas?

  • almost no forces of attraction and particles have more energy so they are free to move and travel in random directions at high speeds
  • generally less dense than liquids and solids
• how do you find the density of a regular solid object?

  1. use a balance to measure its mass in kg
  2. measure the length, width and height using a ruler and calculate the volume
  3. divide the mass by the volume to calculate the density
• how do you find the density of a irregular solid object?

  1. measure the mass of the object
  2. submerge the object in a eureka can filled with water and the water dispersed will be transferred to a measuring cylinder
  3. record the volume in the measuring cylinder which is the volume of the object
  4. divide the mass by the volume to calculate the density
• how do you find the density of a liquid?

  1. put a measuring cylinder on the balance and zero the balance
  2. pour 10ml of liquid into the cylinder and record the mass and repeat adding another 10 ml until the cylinder is full
  3. for each measurement use the formula to find the density
  4. take an average of the densities
• what is 1 ml in cm3?

  1 ml = 1 cm3
• what is internal energy


  the energy stored by the particles making up a system
• specific heat capacity

  • heating the system transfers energy to its particles, increasing internal energy
  • leads to a change in temperature or a change in state
• what is the change from a solid to a gas?

  sublimation