P3

• What is the formula for density?

  Density (ρ) = mass (m) / volume (V)
• What are the units for density?

  Density is measured in kg/m³
• What are the characteristics of solids, liquids, and gases in terms of particle arrangement, forces, distance, and motion?

  • Solid: Regular arrangement, strong forces, very small distance, vibrates only.
  • Liquid: Irregular arrangement, weak forces, small distance, moves slowly.
  • Gas: Irregular arrangement, very weak forces, large distance, moves fast.
• What happens to density when a substance changes from solid to liquid to gas?

  Density decreases as the state changes from solid to liquid to gas.
• What type of changes are changes of state?

  Changes of state are physical changes.
• Is mass conserved during changes of state?

  Yes, mass is always conserved.
• What are the processes involved in changing states of matter?

  • Solid to Liquid: Melting
  • Liquid to Gas: Boiling or Evaporating
  • Gas to Liquid: Condensing
  • Liquid to Solid: Freezing
  • Solid to Gas: Sublimation
• What is internal energy?

  Internal energy is the total energy stored by the particles in a system.
• What components make up the internal energy of a system?

  Internal energy is the total amount of kinetic and potential energy of all its particles.
• What effect does heating have on the internal energy of a system?

  Heating increases the internal energy of a system.
• What are the two possible outcomes of increasing the internal energy of a system?

  It can either increase the temperature or change the state.
• What happens during melting and boiling in terms of particle behavior?

  1. Bonds between particles are broken.
  2. Internal energy increases as energy is transferred to potential energy stores.
  3. Temperature stays the same.
• What happens during condensing and freezing in terms of particle behavior?

  1. Stronger bonds form between particles.
  2. Internal energy decreases as energy is transferred away from potential energy stores.
  3. Temperature stays the same.
• What is specific heat capacity?

  Specific heat capacity is the amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C.
• 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 amount of energy needed to change 1 kg of a substance from one state to another without changing its temperature.
• What is specific latent heat of fusion?

  Specific latent heat of fusion is the specific latent heat of changing between a solid and a liquid.
• What is specific latent heat of vaporisation?

  Specific latent heat of vaporisation is the specific latent heat of changing between a liquid and a gas.
• How does temperature affect the average energy of gas particles?

  The higher the temperature, the higher the average energy in the kinetic energy stores of the gas particles.
• What causes gas pressure?

  Gas pressure is caused by gas particles colliding with a surface and exerting a net force on it.
• What happens to gas pressure when the volume of a gas changes?

  • Pressure outside > Pressure inside: Gas is compressed.
  • Pressure outside < Pressure inside: Gas expands.
• What happens to gas particles when the temperature increases at constant volume?

  Particles get faster and collide with the container more often.
• What happens to gas particles when the volume increases at constant temperature?

  Particles spread out and collide with the container less often.
• What occurs when work is done on a gas?

  Work is done as energy is transferred, increasing the internal energy of the gas.
• What happens to the temperature of an enclosed gas when work is done on it?

  The temperature of the enclosed gas increases.
• How does the temperature of a tyre change when work is done on the air inside it?

  The tyre temperature increases.