Topic 3

• What are the three states of matter?

  Solids, liquids, and gases
• What is density defined as?

  Mass per unit volume
• How is density measured?

  In kg/m³
• What is the formula for density?

  ρ = m/v
• What happens to mass during changes of state?

  Mass is always conserved
• What is the process of melting?

  Solid → Liquid
• What is the process of evaporation?

  Liquid → Gas
• What is the process of condensation?

  Gas → Liquid
• What is sublimation?

  Solid → Gas without becoming liquid
• What does internal energy refer to?

  Total kinetic and potential energies of particles
• How do particles behave in solids?

  They vibrate about fixed positions
• How do particles behave in liquids?

  They can flow over each other
• How do particles behave in gases?

  They move freely
• Which state of matter has the highest density?

  Solids
• Which state of matter has the lowest density?

  Gases
• Which state of matter has the least kinetic energy?

  Solids
• Which state of matter has the most kinetic energy?

  Gases
• What distinguishes physical changes from chemical changes?

  • Physical changes: properties can be recovered
  • Chemical changes: original properties cannot be easily recovered
• What type of changes are changes of state?

  Physical changes
• What is the definition of latent heat?

  Energy required to change state without temperature change
• What is the latent heat of fusion?

  Energy to change from solid to liquid
• What is the latent heat of vaporisation?

  Energy to change from liquid to vapour
• What is the formula for calculating energy change during a temperature change?

  ΔE = m c Δ��
• What is the unit of pressure?

  Pascal
• What does pressure produce in a gas?

  A force at right angles to the container
• What happens when work is done on a gas?

  Temperature increases
• What happens to the temperature of a gas in a bike pump when compressed?

  Temperature increases
• What factors affect temperature increases in materials?

  Material type, mass, and energy inputted
• What is the energy required to raise the temperature of 1kg of a substance by 1°C called?

  Specific heat capacity
• What are the key concepts related to changes of state?

  • Melting: Solid → Liquid
  • Evaporation: Liquid → Gas
  • Condensation: Gas → Liquid
  • Sublimation: Solid → Gas without liquid
• What are the key concepts related to latent heat?

  • Latent Heat of Fusion: Solid to liquid
  • Latent Heat of Vaporisation: Liquid to vapour
  • Formula: ΔE = m L
• What are the key concepts related to pressure in gases?

  • Pressure produces force at right angles
  • Unit of pressure: Pascal
  • pV = constant at constant temperature