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Spectroscopy in Large Lecture Halls
Shows the color spectra of white light and the spectral lines of neon and
mercury and various salts.
Procedure
1" x 1" diffraction gratings are passed out to the class, room lights are dimmed,
and the class views light from an incandescent light and discharge tubes.
Can also burn salts using nichrome wire and Bunsen burner flame. This can
only be done in 2722 York. No other lecture halls have gas lines.
Burning salts
Alternate demo is burning a mix of 1 molar solutions of the following
salts mixed with 40% methanol in recrystalling dishes.
- Set the crystalizing dishes on an asbestos pad or other heat/flame resistant
surface.
- Pour about 10-20 mL onto the bottom of each respective crystilizing dish.
(You want to just cover the bottom of the dish).
- Light the salt mixture with a long match or wooden stick. (Do not drop
a match into the solution or you will get sodium (from the match) in the
salt solution).
- Carefully squirt methanol from the wash bottle into the crystalizing
dish. This gets the solution to burn hotter and brings out the color of
the salt.
| Salt |
Flame Color |
| LiCl |
Red |
| NaCl |
Yellow |
| KCl |
Lilac |
| CaCl2 |
Bright Orange |
| SrCl2 |
Red Orange |
| BaCl2 |
Green |
| RbCl2 |
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