Internal Energy and Energy Transfers

• 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 total kinetic and potential energies
• How does heating affect the energy of a substance?

  It increases the energy of the particles
• What does heating transfer to a substance?

  Energy
• What two effects can heating a substance have?

  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 is specific heat capacity?

  Energy needed to raise 1kg by 1°C
• What are the appropriate units for energy, mass, specific heat capacity, and temperature in the heating equation?

  Energy (J), Mass (kg), Specific Heat Capacity (J/kg/°C), Temperature (°C)
• How do internal energy and temperature change during a change of state?

  • Internal energy increases or decreases
  • Temperature remains constant
• What is specific latent heat?

  Energy needed to change state of 1kg
• What is the specific latent heat of fusion?

  Energy to change 1kg solid to liquid
• What is the specific latent heat of vaporisation?

  Energy to change 1kg liquid to gas
• What is the equation for the energy required to change state?

  • Energy to change state = mass x specific latent heat
  • Units: Energy (J), Mass (kg), Specific latent heat (J/kg)