Thermal

• What is the definition of the triple point?

  It is the unique temperature and pressure where all three phases coexist.
• What does thermal equilibrium mean?

  It is when two objects reach the same temperature.
• What is the kinetic model?

  It describes matter as composed of atoms or molecules.
• What is internal energy?

  It is the sum of kinetic and potential energies of particles.
• What is specific heat capacity?

  It is the energy required to change temperature by 1 K.
• What happens to thermal energy when one object is hotter than another?

  It flows from the hotter object to the colder object.
• What does the Zeroth law of thermodynamics state?

  If A and B are in equilibrium with C, then A and C are in equilibrium.
• How is temperature measured on the Celsius scale?

  Using the freezing and boiling points of water as fixed points.
• Why is the Celsius scale not perfect?

  Because fixed points vary with atmospheric pressure.
• What is the absolute scale based on?

  It uses absolute zero and the triple point of water.
• How does the kinetic model describe solids?

  Atoms are closely packed and vibrate in fixed positions.
• What happens to particles in a solid when heated?

  They gain kinetic energy and vibrate more vigorously.
• How are liquids described in the kinetic model?

  Particles are close together but can move freely.
• What occurs when a liquid is heated?

  Some particles gain energy and escape as gas.
• How are gases described in the kinetic model?

  Particles are far apart and move randomly.
• What is Brownian motion?

  It is the random movement of particles in a fluid.

  
• What causes the random motion of smoke particles?

  Air molecules striking the smoke particles.
• How does the density of substances vary in different phases?

  Solids are generally denser than gases.
• Why is solid water less dense than liquid water?

  Hydrogen bonds hold molecules further apart in ice.
• What is the internal energy of a substance at absolute zero?

  It is at a minimum, with zero kinetic energy.
• How does increasing temperature affect internal energy?

  It increases the average kinetic energy of particles.
• What happens during a phase change regarding temperature?

  Temperature remains constant while potential energy increases.
• What occurs at the melting or boiling point of a substance?

  Energy increases potential energy without raising temperature.
• How does electrostatic potential energy vary in different phases?

  It is lowest in solids and highest in gases.
• What is the specific heat capacity of a substance?

  It is the energy required to change temperature by 1 K.
• What is the formula for specific heat capacity?

  $E =$$mc \Delta \theta$
• Which substance has an exceptionally high specific heat capacity?

  Water