heating and cooling graphs

• What is internal energy?

  Energy stored inside a system by particles
• What types of energy are included in internal energy?

  Kinetic and potential energy of particles
• What does potential energy depend on in particles?

  Forces between particles and atomic bonds
• What happens to a solid substance when it is heated?

  • Temperature rises as energy increases
  • At melting point, it changes to liquid
  • Energy weakens forces of attraction
• What is the term for the energy needed for a substance to change state?

  Latent heat
• What happens to internal energy during a change of state?

  It increases, but temperature remains constant
• How can you find the melting point from a heating graph?

  By reading off the horizontal line
• What occurs when all of the solid has melted?

  The temperature starts to rise again
• What is the term for the point where a substance boils?

  Boiling point
• What happens to the temperature during boiling?

  It stops increasing and becomes horizontal
• What does a cooling graph show when a gas is cooled down?

  • Temperature decreases as energy is lost
  • Gas changes to liquid (condensation)
  • Liquid changes to solid (freezing)
• What is the process called when a gas changes to a liquid?

  Condensation
• What is the process called when a liquid changes to a solid?

  Freezing
• What should you be able to do after watching the video?

  Interpret heating and cooling graphs