P3: Internal Energy & Energy Transfers Physics GCSE

• What is internal energy defined as?

  Total energy stored inside a system
• What are the two types of energy stored in molecules?

  Kinetic and potential energy
• What does the kinetic store of energy in molecules depend on?

  Random motion and vibration of particles
• What does the potential store of energy in molecules depend on?

  Position relative to each other
• How does heating a system affect its internal energy?

  It increases the kinetic energy of particles
• How is temperature related to the kinetic energy of molecules?

  Higher temperature means higher kinetic energy
• What happens to gas molecules when a container is heated?

  They move faster with higher kinetic energy
• What occurs when a substance reaches a certain temperature during heating?

  Energy transfers to the potential store instead
• What is the effect of energy transfer on the temperature during a change of state?

  Temperature remains constant during the change
• What happens to the potential energy of molecules during a change of state?

  It increases to overcome intermolecular forces
• What is the specific heat capacity equation?

  ΔE = mcΔθ
• What does specific heat capacity measure?

  Energy needed to raise 1 kg by 1 °C
• How does a low specific heat capacity affect a substance?

  It heats up and cools down quickly
• Why is water's high specific heat capacity beneficial?

  It remains hot in a radiator for long
• How do you calculate energy transferred to water with mass 0.48 kg and temperature change 0.7 °C?

  Use ΔE = mcΔθ
• What is the energy transferred to 0.48 kg of water raised by 0.7 °C?

  1400 J
• What is latent heat?

  Energy needed for a substance to change state
• What happens to temperature during a change of state?

  It remains constant despite energy transfer
• What are the two types of latent heat?

  Latent heat of fusion and vaporisation
• What is specific latent heat?

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

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

  Energy to convert 1 kg between liquid and gas
• What happens to temperature when a liquid is vaporised?

  It stays constant until all vaporised
• What happens to temperature when a gas is condensed?

  It stays constant until all condensed
• What is the latent heat of fusion's effect on temperature during melting?

  Temperature stays constant until melted
• What is the latent heat of vaporisation's effect on temperature during vaporisation?

  Temperature stays constant until vaporised
• What is the significance of latent heat in phase changes?

  It allows molecules to overcome intermolecular forces
• What is the specific latent heat of vaporisation defined as?

  Energy to convert 1 kg liquid to gas
• When does the temperature of a liquid stay constant during vaporisation?

  Until all the substance has vaporised
• What does the latent heat of vaporisation represent?

  Energy per kg to overcome intermolecular forces
• At what temperature does a gas condense?

  At its boiling point
• What happens to energy when a gas condenses?

  Energy is transferred away from the substance
• What must be included in the definition of specific latent heat for full marks?

  'With no change in temperature'
• What is the equation for calculating energy required for a change in state?

  E = mL
• What do the symbols in the equation E = mL represent?

  E is energy, m is mass, L is latent heat
• If the mass is 0.60 kg and the specific latent heat is 199,000 J/kg, what is the energy required?

  119,400 J
• What happens to temperature during melting?

  Temperature stays constant until melting is complete
• What is the effect of heating on a solid's particles?

  Particles gain kinetic energy and vibrate faster
• What occurs when a substance reaches its boiling point?

  Temperature stays constant while vaporising
• What is the process called when a gas turns into a liquid?

  Condensation