today n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Today: PowerPoint Presentation
Download Presentation
Today:

Loading in 2 Seconds...

play fullscreen
1 / 6

Today: - PowerPoint PPT Presentation


  • 136 Views
  • Uploaded on

Today:. Quiz Comments Practice for Melting Point Ranges and Recrystallization Introduction to Molecular Modeling (Lab today is in SEGA lab Science249).

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Today:' - winter


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
today
Today:
  • Quiz Comments
  • Practice for Melting Point Ranges and Recrystallization
  • Introduction to Molecular Modeling

(Lab today is in SEGA lab Science249)

slide2

Melting point ranges for mixtures of compounds A and BPhase DiagramWhat is the mp. and mol% composition of the eutectic mixture?What is the mp. range of mixture X?

oC

oC

140

Pure B

Pure A

X

100

80

60

60

40

E

20

20

Solid A and B

mol%A

mol%B

100%A

100%B

75%A

25%B

50%A

50%B

25%A

75%B

the following solubility data were collected before recrystallizing a sample of caffeine c
The following solubility data were collected before recrystallizing a sample of caffeine (C):

Solvent Sol. Of C at 20o Sol of C in hot solvent

Water slightly soluble soluble

Ethanol soluble soluble

Acetone soluble soluble

Benzene slightly soluble soluble

Pet. Ether insoluble insoluble

1) Which single solvent(s) could you use for recrystallization?

2) Suggest a mixed solvent pair that you could use instead.

solubility data for caffeine
Solubility Data for Caffeine

1.000g of caffeine completely dissolves in a minimum of

  • 45.0ml of water at 14oC
  • 5.5 ml of water at 80oC
  • 1.5 mL of boiling water

Assume that you are recrystallizing 2.000g of impure caffeine.

After one recrystallization from 30.0 ml of water you ended up with 1.200 g of purified caffeine. How many grams of caffeine were left in the cooled water? (careful …)

If you reduced the volume of the mother liquor to 5 ml, how many grams of caffeine would be left in solution in the cooled solution?

molecular modeling
Molecular Modeling

Remember these:

Hybridization of C

Bond length, angle, dihedral angle; staggered and eclipsed conformations

Conformations of cyclohexane; axial , equatorial substituents

We’ll do MM Exps. 1, 2, 4, only

slide6
Next time:Distillation/Gas Chromatography (Exp.3)(Notebook preparation please… Preview/prestudy experiment)