The particle model

• For a solid, describe 1) the arrangement and 2) the movement of particles in a solid.

  Particles close together, regular order.

  Particles vibrate in fixed positions.
• For liquid, describe 1) the arrangement and 2) the movement of particles.

  Particles close together, not in regular order.

  Particles move around each other.
• For a gas, describe 1) the arrangement and 2) the movement of particles.

  Particles far apart.

  Particles move freely and randomly.
• Describe the force between particles in solids, liquids and gases.

  Solids - strong forces between particles.

  Liquids - weaker forces between particles.

  Gases - no (significant) forces between particles.
• Define internal energy.

  The total kinetic energy and the total potential energy of all the particles.
• What happens to the particles in a substance if its temperature is increased?

  The particles move faster (have more kinetic energy).
• What happens to the particles in a substance when it changes state.

  The particles move relative to each other.
• What do the flat sections on a heating or cooling graph show

  Change of state.
• What happens to a substance when its particles gain kinetic energy?

  The temperature rises (because particles move faster).
• What is specific heat capacity?

  Energy required to raise the temperature of 1kg of a substance by 1°C.
• What happens to a substance when its particles gain potential energy?

  Changes state (particles can move further apart).
• What is specific latent heat?

  Energy required to change the state of 1kg of a substance (without changing temperature).
• How can you calculate density?

  density = mass / volume.
• Why are solids denser than gases?

  The particles are closer together in a solid.
• How can you find the mass of a substance?

  Balance.
• How can you find the volume of a regular solid?

  Length x width x height.
• How can you find the volume of an irregular solid?

  Displacement (using Eureka can or measuring cylinder).
• How can you find the volume of a liquid?

  Measuring cylinder.
• What causes gas pressure?

  Force of particles colliding with the surface of the container.
• Give two reasons why gas pressure increases with increasing temperature.

  Particles move faster so 1) more collisions with surface and 2) more force of collisions.