Chemistry ch 17

  1. as the temperature of a solid increases, what else increases?
    velocity of the particles
  2. when are melting point and freezing point the same?
    at the same pressure
  3. melting point
    particles slip out of their organized pattern and the solid becomes a liquid
  4. freezing point
    particles of the liquid move so slowly that they move back into an organized pattern
  5. vapor
    particles move so fast that the liquid becomes vapor
  6. equilibrium
    • that state in which 2 opposing processes occur at an equal rate
    • requires a closed system
  7. dynamic equilibrium
    particles are constantly moving from or returning to the liquid
  8. saturated
    when the liquid is in equilibrium with the vapor above it
  9. the high the temperature, the higher the _____ gases exert
  10. Le Chatelier's principle
    • when a system in equilibrium is stressed, the system will react to relieve the stress
    • change in temperature, pressure, and concentration
  11. vapor pressure
    the pressure generated by a vapor that is in equilibrium with a liquid
  12. Low vp has what kind of intermolecular forces?
    strong- hold particles tightly
  13. high vp has what kind of intermolecular forces
    weak- hold particles weakly
  14. melting point (solid)
    the temp at which the vp of the solid and the vp of the liquid are equal
  15. sublimation
    • solids that vaporize quickly in air without going through the liquid phase
    • dry ice, moth balls
  16. What happens when temperature rises in a lquid?
    • vp and ke also increase
    • molecules get pushed further apart
    • bubbles of vapor form and the move to the liqid's surface
  17. normal bp
    the vp in a system is equal to the standard atmospheric pressure- 101.3 kPa
  18. BP is a function of
    • air pressure
    • the lower the air pressure, the lower the bp
  19. what is the difference between boiling and evaporation?
    • evaporation occurs at the surface
    • boiling occurs throughout
  20. volatile
    boils at low temp and evaporates quickly at room temperature
  21. non-volatile
    boils at high temp and evaporates slowly at room temperature
  22. what kind of vp's do volatile liquids have?
  23. what kind of vp's do non-volatile liquids have?
    low vp
  24. liquefaction
    condensing substances that are normally gases at room temp to liquids- involves temp and pressure
  25. critical temp
    • Tc
    • temp above which no amount of pressure will result in the liquefaction of a gas
  26. critical pressure
    • Pc
    • the pressure that will cause a gas to liquefy at Tc
  27. Low Tc indicates
    weak forces between molecules
  28. High Tc indicates
    strong forces between between molecules
  29. phase diagram
    shows the relationship between temperature, pressure, and physical state
  30. triple point
    the temp and pressure at which all 3 phases are at equilibrium
  31. when energy is added to a solid, the temp of the solid increases until
    Tm is reached
  32. the temperature of a melting solid doesn't change until
    all of the solid is completely melted
  33. What does the energy added to a solid need to change?
    the position of the particles- PE is increased
  34. enthalpy of fusion
    the energy required to melt 1 gram of a substance at its Tm
  35. ^Hfus of ice
    334 j/g
  36. enthalpy of vaporization
    the energy required to vaporize 1gram of a substance at its Tb
  37. ^Hvap of water
    2260 j/g
  38. melting and boiling points for molecules can be predicted with a knowledge of
    the atomic and molecular structure
  39. melting and boiling points for molecules can be predicted with a knowledge of the atomic and molecular structures unless
    • the molecules contain H that is covalently bonded to a highly electronegative atom
    • highly polar molecule
  40. hydrogen bonding forms?
    extremely strong dipole
  41. what does H bond with to form these dipoles?
    • N, O, F
    • NH3, H2O, HF
  42. when is water most dense?
    3.98 deg C
  43. what breaks H bonds?
  44. in ice, one molecule of water is bonded to ____ other water molecules
  45. the clusers of hydrogen bonds in ice creat what?
    • crystalline structure
    • many open spaces
  46. surface tension is due to
    the unbalanced forces on the surface particles of a liquid
  47. what kind of surface tension does water have?
  48. what kind of surface tension does mercury have?
Card Set
Chemistry ch 17