Internal Energy

• What does internal energy include?

  Kinetic and potential energy of particles
• What is kinetic energy in the context of internal energy?

  Energy due to the speed of molecules
• What contributes to potential energy in a substance?

  Intermolecular forces and particle separation
• How is internal energy defined?

  Sum of kinetic and potential energies of particles
• What does the symbol U represent?

  Internal energy of a substance
• What are the units of internal energy?

  Joules (J)
• Why are particles described as randomly distributed?

  They have different speeds and separations
• What factors determine the internal energy of a system?

  Temperature, motion, phase, and interactions
• How does temperature affect internal energy?

  Higher temperature increases kinetic energy
• Which phase of matter has the highest internal energy?

  Gases
• Which phase of matter has the lowest internal energy?

  Solids
• How can the internal energy of a system increase?

  By doing work or adding thermal energy
• How can the internal energy of a system decrease?

  Losing thermal energy or doing work
• What should you include in the definition of internal energy for exams?

  Random motion or distribution of energies
• What happens to internal energy when a gas pushes a piston?

  It decreases as work is done
• What is the effect of adding thermal energy to a system?

  It increases the internal energy