Specific latent heat

• What is the maximum temperature water can reach on a stove?

  100 °C
• Why does heating water not increase its temperature above 100 °C?

  Because of latent heat during phase changes
• What happens to energy when heating a solid or liquid?

  It transforms into kinetic energy of particles
• What is the role of energy when a substance is melting or boiling?

  It is used to break bonds between particles
• What occurs when a substance is condensing or freezing?

  Bonds are forming between particles, releasing energy
• How does the temperature change during melting or boiling compared to freezing or condensing?

  Temperature remains constant during phase changes
• What is the procedure to observe the effects of heating ice in a beaker?

  1. Fill a beaker with crushed ice.
  2. Place a thermometer in the beaker.
  3. Gradually heat the beaker using a Bunsen burner.
  4. Record the temperature every twenty seconds.
  5. Continue until the water begins to boil.
  6. Plot a graph of temperature against time.
• What should the graph of temperature against time show during the experiment with ice?

  It should show changes in state at constant temperature
• What does the flat part of the graph indicate during the heating of ice?

  It indicates a change of state at constant temperature
• What is the difference between specific latent heat and temperature rise?

  Specific latent heat relates to state change
• What is the formula for specific latent heat?

  Specific latent heat = Energy needed to change state
• What does specific latent heat measure?

  Energy needed to change the state of a substance
• How does specific latent heat relate to temperature changes?

  It measures energy for state changes, not temperature
• What do the flat spots on the graph show?

  A change of state at constant temperature
• How does specific heat capacity relate to temperature rise?

  It relates to a temperature rise of 1°C
• What is specific latent heat of a substance?

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

  Heat for changing solid to liquid at constant temperature
• What is the specific latent heat of vaporization?

  Heat for changing liquid to gas at constant temperature
• How can you calculate the thermal energy needed for a substance?

  Using the formula: Q = m × L
• What units is thermal energy given in?

  Joules (J)
• What does the specific latent heat depend on?

  It varies for different materials and states
• How does the specific latent heat of fusion differ from vaporization?

  Fusion is solid to liquid; vaporization is liquid to gas
• How much energy is needed to melt 250 g of a substance with a specific latent heat of fusion of $1200000 \text{ J/kg}$?


  $300000 \text{ J}$
• What is the specific latent heat of vaporization for a substance?

  Energy needed to change liquid to gas
• What happens to energy when a substance changes state?

  Energy is absorbed or released without temperature change
• How do you calculate the thermal energy released during cooling?

  Using the formula: Q = m × L
• How does exercising affect the energy needed for state changes?

  It increases energy needed to change liquids to gases
• What is the specific latent heat of fusion for a particular substance?

  1200000 J/kg
• What does the term "specific latent heat" refer to?

  Energy required to change the state of a substance
• How does the energy needed for melting compare to that for boiling?

  Melting requires specific latent heat of fusion; boiling requires vaporization
• What is the formula for calculating thermal energy?

  Q = m × L
• What is the significance of the specific latent heat in physical processes?

  It determines energy changes during state transitions
• How does the specific latent heat affect the melting of ice?

  It dictates the energy required to melt ice
• How does the specific latent heat of vaporization affect boiling water?

  It determines the energy needed to convert water to steam
• What is the specific latent heat of fusion for a substance?

  1200000 J/kg
• What happens to energy during the melting process?

  Energy is absorbed without temperature change
• How much energy is needed to melt 250 g of a substance with a specific latent heat of fusion of $1200000 \text{ J/kg}$?


  $300000 \text{ J}$
• How does the specific latent heat of fusion differ from that of vaporization?

  Fusion is solid to liquid; vaporization is liquid to gas
• What is the specific latent heat of vaporization for a substance?

  Energy needed to change liquid to gas
• What does the term "specific latent heat" refer to?

  Energy required to change the state of a substance