Particle model of matter

• Density = mass / volume
• What do you use to measure the volume of an irregular object

  Eureka can
• How are particles in a solid

  • are in a regular arrangement
  • vibrate about a fixed position
  • sit very closely together
• How are particles in a liquid

  • are randomly arranged
  • move around each other
  • sit close together
• How are particles in a gas

  • are randomly arranged
  • move quickly in all directions
  • are far apart
• Adding or removing energy from a material can change its state. Heating a solid material will cause it to melt from a solid to a liquid. Continued heating will cause the liquid to boil or evaporate to form a gas. In some instances, a solid material can go straight to being a gas without first becoming a liquid when heated. This process is called sublimation.
• The specific heat capacity of a material is the energy required to raise one kilogram (kg) of the material by one degree Celsius (°C).
• change in thermal energy = mass × specific heat capacity × temperature change
• Specific latent heat is the amount of energy required to change the state of 1 kilogram (kg) of a material without changing its temperature.
• change in thermal energy = mass × specific latent heat
• The particles in a gas are moving very quickly in random directions. The speeds of the particles vary but, on average, they move quicker than they do in liquids and solids.
• Pressure = force / area
• Since the particles in a gas are moving fast and randomly, collisions occur frequently. These collisions may be between two particles, between a particle and the wall of the container, or between a particle and something else in the container.
• The temperature of a gas is a measure of the average kinetic energy of its particles - the higher the temperature, the higher the average kinetic energy.
• pressure × volume = constant
• How can pressure be increased

  • increasing the temperature - this increases the force of each collision
  • decreasing the volume - this increases the number of collisions per second