Internal Energy and Heat Capacity

• What concept relates internal energy to temperature?

  Specific heat capacity
• What is internal energy?

  Total energy stored by particles
• What are the two parts of internal energy?

  Potential energy stores and kinetic energy stores
• Which type of energy is important for temperature changes?

  Kinetic energy
• How does heating a substance affect its internal energy?

  It increases the kinetic energy of particles
• What does temperature measure in a substance?

  Average internal energy of the substance
• How much energy does water require to warm by one degree Celsius?

  4200 joules
• How much energy is needed to heat one kilo of mercury by one degree Celsius?

  139 joules
• What is specific heat capacity?

  Energy needed to raise temperature of one kilo
• What happens when one kilo of water cools by one degree Celsius?

  It releases 4200 joules of energy
• What is the equation for change in internal energy?

  ΔU = m × c × Δθ
• How do you find the change in temperature using energy, mass, and specific heat capacity?

  Δθ = E / (m × c)
• What is the initial temperature of the water in the example?

  20 degrees Celsius
• What is the mass of water used in the example?

  800 grams
• How much energy is transferred to the water in the example?

  20 kilojoules
• What is the final temperature of the water after energy transfer?

  25.95 degrees Celsius
• Why might the temperature not increase as much in real life?

  Some energy is lost to surroundings
• What are the steps to calculate the final temperature of water after energy transfer?

  1. Identify initial temperature and mass.
  2. Convert mass to kilograms if necessary.
  3. Convert energy to joules if necessary.
  4. Use the equation Δθ = E / (m × c).
  5. Add the change in temperature to the initial temperature.
• What factors affect the specific heat capacity of materials?

  • Type of material
  • Molecular structure
  • Bonding forces
  • Temperature range
• What precautions should be taken during the experiment to measure temperature changes?

  • Use a lid to minimize heat loss
  • Insulate the container well
  • Ensure accurate measurements of mass and energy