Thermo, set 1

  1. system
    a quantity of matter or a region in space chosen for study
  2. surroundings
    physical space outside the system boundary
  3. boundary
    real or imaginary surface that separates the system from its surroundings. It may be fixed or movable.
  4. closed system
    exchange of energy but NOT matter
  5. open system
    (control volume), exchange of energy and matter
  6. control surface
    boundary of an open system
  7. isolated system
    can exchange NEITHER energy nor matter
  8. property
    a characteristic of a system in equilibrium. It is independent of the path used to arrive at the system condition.
  9. Intensive property
    independent of amount of material (i.e.temperature, pressure, age, color, etc.)

    Ratio of two extensive = intensive
  10. extensive property
    Dependent of amount of material (mass, volume, total energy, etc.)
  11. weight
    a force. W = mg
  12. equilibrium
    a system that maintains thermal (uniform temperature), mechanical (uniform pressure), phase (mass of two phases), and chemical equilibrium. Microscopic processes still occur and rate of process is balances by reverse process.
  13. Process
    Any change from one state to another
  14. steady-flow process
    operating for long periods of time under the same conditions
  15. state postulate
    a thermodynamic state of a simple compressible sysem is completely specified by two independent, intensive properties
  16. cycle
    a process with identical end states
  17. Pressure
  18. absolute pressure
    • measured relative to absolute zero (absolute vacuum)
    • P abs = P atm +/- P gage
  19. atmospheric pressure
    aka gage or vacuum pressure
  20. Temperature
    energy content of a mass
  21. heat
    • (Q) transfer; the difference in temperature that causes energy to flow between bodies
    • Also difference in enthalpy!
  22. zeroth law of thermo
    if two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other
  23. Phase
    physically homogeneous/mechanically separable part of system (i.e. vapor, liquid, mineral)
  24. component
    Expresses compositional variations in system. H20 is one-component system, only if phases are interest
  25. Energy states
    • Unstable: falling/rolling
    • Stable: at rest in LOWEST energy state
    • Metastable: in low-energy perch
    • equilibrium is NOT steady state
  26. thermal equilibrium
    No net transfer of energy as heat between two regions contacted by diathermic wall (same temp). Different temp, heat would flow from hot to cold region.
  27. Mechanical Equilibrium
    Two regions separated by a wall have equal pressure. But if one region had high pressure, it would move the wall toward the region with low pressure.
  28. reversible
    Idealized process, proceeds through sequence of equilibrium states. No finite deviation from equilibrium.
  29. spontaneous
    real/natural process where internal state of system changes to approach equilibrium from initial non-equilibrium state
  30. Endothermic
    absorbs heat (+Q, or delta H > 0 )
  31. Exothermic
    releases heat (-Q, or delta H < 0)
Card Set
Thermo, set 1
Chemical Thermodynamics