Physics- Thermal Physics.txt

Card Set Information

Physics- Thermal Physics.txt
2013-05-05 03:51:31
Physics IB

Show Answers:

  1. Define specific heat capacity
    • The energy required to change the temperature (of a substance) by 1℃/1K;
    • of mass 1kg / per unit mass.
  2. 7 Assumptions of an ideal gas
    • Point molecules / negligible volume;
    • No forces between molecule except for in contact;
    • Motion / distribution is random;
    • Elastic collisions / no energy lost;
    • Obey Newton's laws of motion;
    • Collision in zero time;
    • Gravity is ignored;
  3. Define mole
    The molecular weight of the substance in grams / 6.02x10^25 atoms of the substance / same number of particles as in 12g of Carbon-12;
  4. Define internal energy
    Total energy of component particles / comprises of potential energy + (random) kinetic energy. Measured in Joules (J);
  5. Define temperature
    • Measure of average kinetic energy of particles;
    • indicates direction of (natural) flow of thermal energy;
    • measured in Kelvin (K);
  6. Describe cooling by evaporation
    • Faster / more energetic molecules escape during evaporation;
    • slower/ less energetic lower temperature molecules remain;
    • so internal energy removed from body;
  7. Describe the difference in internal energy of a solid and an ideal gas.
    • Internal energy of solid is total KE plus PE of molecules;
    • the molecules of an ideal gas comprises of KE only;
  8. Explain why the latent heat of vaporization is larger than the latent heat of fusion.
    • In boiling, energy is required to break bonds (in vaporization) and to separate molecules;
    • in melting (more) energy is available to overcome bond energies of molecules without large separation;
  9. Distinguish between evaporation and boiling.
    • Evaporation at surface of liquid, boiling occurs throughout liquid;
    • evaporation occurs at all temperatures, boiling at boiling point only;
  10. Define thermal capacity
    Thermal energy required to change temperature by 1K / 1℃;
  11. Define thermal equilibrium
    Rate of energy absorption is equal to the rate of energy emission / temperature of substance remains constant;
  12. Define heating
    The (non-mechanical) transfer of energy;