Particle model of matter

• What does the particle model state about matter?

  Everything is made up of tiny particles.
• How does the particle model explain the three states of matter?

  It describes how particles behave in solids, liquids, and gases.
• What are the characteristics of particles in solids?

  • Strong forces of attraction hold particles close together.
  • Fixed, regular arrangement of particles.
  • Particles vibrate about fixed positions.
  • Highest density among the three states.
• What are the characteristics of particles in liquids?

  • Weaker forces of attraction between particles.
  • Particles are close but can move past each other.
  • More energy than in solids but less than in gases.
  • Move in random directions at low speeds.
  • Generally less dense than solids.
• What are the characteristics of particles in gases?

  • Almost no forces of attraction between particles.
  • Highest energy compared to solids and liquids.
  • Free to move and travel in random directions at high speeds.
  • Low density.
• What does density measure?

  Density measures how much mass is packed into a given volume.
• What are the units of density?

  Density is measured in kg/m³.
• How does density vary between different states of matter?

  Solids are generally denser than liquids, and gases are usually less dense than liquids.
• What happens to the density of a material when it is compressed?

  The particles move closer together, increasing the density.
• What is internal energy and how is it related to changes of state?

  • Internal energy is stored by the particles in a system.
  • Changes of state conserve mass.
  • Heating a liquid causes it to boil and become a gas.
  • Cooling a liquid causes it to freeze.
  • A change of state is a physical change, not a chemical change.
• What is latent heat?

  Latent heat is the energy needed to change the state of a substance.
• What is specific latent heat?

  Specific latent heat is the energy needed to change 1 kg of a substance from one state to another without changing its temperature.
• What is the formula for calculating energy needed for a change of state?

  Energy (E) = Mass (m) × Specific Latent Heat (L)
• How much energy is needed to boil 1.50 kg of water with a specific latent heat of vaporisation of 2,260,000 J/kg?

  3,390,000 J
• How does temperature relate to the average energy of gas particles?

  • The particles in a gas are constantly moving.
  • Increasing the temperature increases the average kinetic energy of the particles.
  • Higher temperature correlates with higher average energy in kinetic stores.
• What happens to the internal energy of a gas when work is done on it?

  The internal energy increases, which can raise its temperature.
• What is the relationship between pressure and volume in gases?

  • A change in pressure can cause a change in volume.
  • Compressing a gas increases its pressure.
  • Expanding a gas decreases its pressure.
• What is the definition of pressure in gases?

  Pressure is the force exerted by gas particles colliding with the walls of their container.
• What is the relationship between specific heat capacity and specific latent heat?

  Specific heat capacity relates to temperature rise, while specific latent heat relates to changes of state.
• What should you be able to describe in an exam regarding the arrangement and movement of particles in solids, liquids, and gases?

  You should be able to describe the arrangement and movement of particles in each state.
• What type of energy change occurs when a liquid freezes?

  A decrease in internal energy occurs when a liquid freezes.
• What is the effect of compressing a gas on its temperature?

  Compressing a gas increases its temperature.
• What is the significance of the diagrams related to particle arrangement and movement?

  They help describe the arrangement and movement of particles in solids, liquids, and gases.