Chapter 6 Sublimation

1
Chapter 6Sublimation
2
Sublimation

• Sublimation is the process whereby a solid
  evaporates from a warm surface and condenses on a
  cold surface as a solid.
• Sublimation is preferred over crystallization for
  lt 100mg purification as there is little loss of
  material.
• Use apparatus shown in Figure 6.21, p. 130. You
  are to use vacuum sublimation for high mp
  substances (gt80oC). Vacuum line is attached to
  the side arm of the filter flask.
• Sublime two known and one unknown substance.
• Determine mass, yield, and mp for unknown
  characterization (Table 6.3, p. 132).
• NOTE Do NOT get water in the apparatus

3
Postlab Questions(also stated in the lab handout)

• What is the preparative benefit of sublimation?
• Cite some example of substances that sublime.
  According to your experience, how can one improve
  the sublimation process?