3.2

• What is the internal energy of a substance?

  The energy stored by the particles
• What does the internal energy of a substance consist of?

  The sum of the total kinetic and potential energies that make up the system
• How does heating affect the energy of a substance?

  Heating transfers energy to the substance
• What happens to the energy of the particles in a substance when it is heated?

  It increases the energy of the particles that make up the substance
• What two things can heating a substance do?

  1. Raise its temperature
  2. Change the state of the substance
• What three factors determine the temperature change of a system?

  1. Mass of substance being heated
  2. Type of material (Specific heat capacity)
  3. Energy inputted into the system
• What is the equation used to calculate the temperature change when a substance is heated?

  ΔE = m c Δ��
• What are the appropriate units for the variables in the equation ΔE = m c Δ𝛉?

  Energy (J), Mass (kg), Specific Heat Capacity (J/kg/°C), Temperature (°C)
• What is specific heat capacity?

  The amount of energy needed to increase the temperature of 1kg of a substance by 1°C
• How does the internal energy and temperature of a substance change when a change of state occurs?

  • The internal energy of the substance will be increased or decreased
  • The temperature of the substance will remain constant
• What is specific latent heat?

  The amount of energy needed to change the state of 1kg of a substance with no change in temperature
• What is the equation for the energy required to change state?

  Energy to change state = mass x specific latent heat
• What are the appropriate units for the equation Energy to change state = mass x specific latent heat?

  Energy (J), Mass (kg), Specific latent heat (J/kg)
• What is the specific latent heat of fusion?

  The energy required to change 1kg of a substance from solid state to liquid state without a change in temperature
• What is the specific latent heat of vaporisation?

  The energy required to change 1kg of a substance from liquid state to gas state (vapour) without a change in temperature